435 lines
14 KiB
LLVM
435 lines
14 KiB
LLVM
; RUN: opt < %s -analyze -enable-new-pm=0 -scalar-evolution | FileCheck %s
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; RUN: opt < %s -disable-output "-passes=print<scalar-evolution>" 2>&1 | FileCheck %s
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; ScalarEvolution should be able to understand the loop and eliminate the casts.
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; CHECK: {%d,+,4}
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define void @foo(i32* nocapture %d, i32 %n) nounwind {
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entry:
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%0 = icmp sgt i32 %n, 0 ; <i1> [#uses=1]
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br i1 %0, label %bb.nph, label %return
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bb.nph: ; preds = %entry
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br label %bb
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bb: ; preds = %bb1, %bb.nph
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%i.02 = phi i32 [ %5, %bb1 ], [ 0, %bb.nph ] ; <i32> [#uses=2]
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%p.01 = phi i8 [ %4, %bb1 ], [ -1, %bb.nph ] ; <i8> [#uses=2]
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%1 = sext i8 %p.01 to i32 ; <i32> [#uses=1]
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%2 = sext i32 %i.02 to i64 ; <i64> [#uses=1]
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%3 = getelementptr i32, i32* %d, i64 %2 ; <i32*> [#uses=1]
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store i32 %1, i32* %3, align 4
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%4 = add i8 %p.01, 1 ; <i8> [#uses=1]
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%5 = add i32 %i.02, 1 ; <i32> [#uses=2]
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br label %bb1
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bb1: ; preds = %bb
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%6 = icmp slt i32 %5, %n ; <i1> [#uses=1]
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br i1 %6, label %bb, label %bb1.return_crit_edge
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bb1.return_crit_edge: ; preds = %bb1
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br label %return
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return: ; preds = %bb1.return_crit_edge, %entry
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ret void
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}
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; ScalarEvolution should be able to find the maximum tripcount
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; of this multiple-exit loop, and if it doesn't know the exact
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; count, it should say so.
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; PR7845
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; CHECK: Loop %for.cond: <multiple exits> Unpredictable backedge-taken count.
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; CHECK: Loop %for.cond: max backedge-taken count is 5
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@.str = private constant [4 x i8] c"%d\0A\00" ; <[4 x i8]*> [#uses=2]
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define i32 @main() nounwind {
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entry:
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br label %for.cond
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for.cond: ; preds = %for.inc, %entry
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%g_4.0 = phi i32 [ 0, %entry ], [ %add, %for.inc ] ; <i32> [#uses=5]
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%cmp = icmp slt i32 %g_4.0, 5 ; <i1> [#uses=1]
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br i1 %cmp, label %for.body, label %for.end
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for.body: ; preds = %for.cond
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%conv = trunc i32 %g_4.0 to i16 ; <i16> [#uses=1]
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%tobool.not = icmp eq i16 %conv, 0 ; <i1> [#uses=1]
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%tobool3 = icmp ne i32 %g_4.0, 0 ; <i1> [#uses=1]
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%or.cond = and i1 %tobool.not, %tobool3 ; <i1> [#uses=1]
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br i1 %or.cond, label %for.end, label %for.inc
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for.inc: ; preds = %for.body
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%add = add nsw i32 %g_4.0, 1 ; <i32> [#uses=1]
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br label %for.cond
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for.end: ; preds = %for.body, %for.cond
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%call = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i32 %g_4.0) nounwind ; <i32> [#uses=0]
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ret i32 0
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}
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declare i32 @printf(i8*, ...)
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define void @test(i8* %a, i32 %n) nounwind {
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entry:
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%cmp1 = icmp sgt i32 %n, 0
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br i1 %cmp1, label %for.body.lr.ph, label %for.end
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for.body.lr.ph: ; preds = %entry
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%tmp = zext i32 %n to i64
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br label %for.body
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for.body: ; preds = %for.body, %for.body.lr.ph
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%indvar = phi i64 [ %indvar.next, %for.body ], [ 0, %for.body.lr.ph ]
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%arrayidx = getelementptr i8, i8* %a, i64 %indvar
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store i8 0, i8* %arrayidx, align 1
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%indvar.next = add i64 %indvar, 1
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%exitcond = icmp ne i64 %indvar.next, %tmp
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br i1 %exitcond, label %for.body, label %for.cond.for.end_crit_edge
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for.cond.for.end_crit_edge: ; preds = %for.body
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br label %for.end
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for.end: ; preds = %for.cond.for.end_crit_edge, %entry
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ret void
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}
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; CHECK: Determining loop execution counts for: @test
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; CHECK-NEXT: backedge-taken count is
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; CHECK-NEXT: max backedge-taken count is 4294967294
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; PR19799: Indvars miscompile due to an incorrect max backedge taken count from SCEV.
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; CHECK-LABEL: @pr19799
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; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count.
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; CHECK: Loop %for.body.i: max backedge-taken count is 1
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@a = common global i32 0, align 4
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define i32 @pr19799() {
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entry:
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store i32 -1, i32* @a, align 4
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br label %for.body.i
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for.body.i: ; preds = %for.cond.i, %entry
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%storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
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%tobool.i = icmp eq i32 %storemerge1.i, 0
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%add.i.i = add nsw i32 %storemerge1.i, 2
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br i1 %tobool.i, label %bar.exit, label %for.cond.i
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for.cond.i: ; preds = %for.body.i
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store i32 %add.i.i, i32* @a, align 4
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%cmp.i = icmp slt i32 %storemerge1.i, 0
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br i1 %cmp.i, label %for.body.i, label %bar.exit
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bar.exit: ; preds = %for.cond.i, %for.body.i
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ret i32 0
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}
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; PR18886: Indvars miscompile due to an incorrect max backedge taken count from SCEV.
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; CHECK-LABEL: @pr18886
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; CHECK: Loop %for.body: <multiple exits> Unpredictable backedge-taken count.
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; CHECK: Loop %for.body: max backedge-taken count is 3
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@aa = global i64 0, align 8
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define i32 @pr18886() {
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entry:
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store i64 -21, i64* @aa, align 8
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br label %for.body
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for.body:
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%storemerge1 = phi i64 [ -21, %entry ], [ %add, %for.cond ]
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%tobool = icmp eq i64 %storemerge1, 0
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%add = add nsw i64 %storemerge1, 8
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br i1 %tobool, label %return, label %for.cond
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for.cond:
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store i64 %add, i64* @aa, align 8
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%cmp = icmp slt i64 %add, 9
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br i1 %cmp, label %for.body, label %return
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return:
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%retval.0 = phi i32 [ 1, %for.body ], [ 0, %for.cond ]
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ret i32 %retval.0
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}
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; Here we have a must-exit loop latch that is not computable and a
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; may-exit early exit that can only have one non-exiting iteration
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; before the check is forever skipped.
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;
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; CHECK-LABEL: @cannot_compute_mustexit
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; CHECK: Loop %for.body.i: <multiple exits> Unpredictable backedge-taken count.
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; CHECK: Loop %for.body.i: Unpredictable max backedge-taken count.
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@b = common global i32 0, align 4
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define i32 @cannot_compute_mustexit() {
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entry:
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store i32 -1, i32* @a, align 4
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br label %for.body.i
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for.body.i: ; preds = %for.cond.i, %entry
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%storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
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%tobool.i = icmp eq i32 %storemerge1.i, 0
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%add.i.i = add nsw i32 %storemerge1.i, 2
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br i1 %tobool.i, label %bar.exit, label %for.cond.i
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for.cond.i: ; preds = %for.body.i
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store i32 %add.i.i, i32* @a, align 4
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%ld = load volatile i32, i32* @b
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%cmp.i = icmp ne i32 %ld, 0
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br i1 %cmp.i, label %for.body.i, label %bar.exit
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bar.exit: ; preds = %for.cond.i, %for.body.i
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ret i32 0
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}
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; This loop has two must-exits, both of which dominate the latch. The
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; MaxBECount should be the minimum of them.
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;
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; CHECK-LABEL: @two_mustexit
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; CHECK: Loop %for.body.i: <multiple exits> backedge-taken count is 1
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; CHECK: Loop %for.body.i: max backedge-taken count is 1
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define i32 @two_mustexit() {
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entry:
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store i32 -1, i32* @a, align 4
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br label %for.body.i
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for.body.i: ; preds = %for.cond.i, %entry
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%storemerge1.i = phi i32 [ -1, %entry ], [ %add.i.i, %for.cond.i ]
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%tobool.i = icmp sgt i32 %storemerge1.i, 0
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%add.i.i = add nsw i32 %storemerge1.i, 2
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br i1 %tobool.i, label %bar.exit, label %for.cond.i
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for.cond.i: ; preds = %for.body.i
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store i32 %add.i.i, i32* @a, align 4
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%cmp.i = icmp slt i32 %storemerge1.i, 3
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br i1 %cmp.i, label %for.body.i, label %bar.exit
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bar.exit: ; preds = %for.cond.i, %for.body.i
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ret i32 0
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}
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; CHECK-LABEL: @ne_max_trip_count_1
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; CHECK: Loop %for.body: max backedge-taken count is 7
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define i32 @ne_max_trip_count_1(i32 %n) {
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entry:
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%masked = and i32 %n, 7
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br label %for.body
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for.body:
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%i = phi i32 [ 0, %entry ], [ %add, %for.body ]
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%add = add nsw i32 %i, 1
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%cmp = icmp ne i32 %i, %masked
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br i1 %cmp, label %for.body, label %bar.exit
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bar.exit:
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ret i32 0
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}
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; CHECK-LABEL: @ne_max_trip_count_2
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; CHECK: Loop %for.body: max backedge-taken count is -1
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define i32 @ne_max_trip_count_2(i32 %n) {
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entry:
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%masked = and i32 %n, 7
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br label %for.body
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for.body:
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%i = phi i32 [ 0, %entry ], [ %add, %for.body ]
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%add = add nsw i32 %i, 1
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%cmp = icmp ne i32 %add, %masked
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br i1 %cmp, label %for.body, label %bar.exit
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bar.exit:
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ret i32 0
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}
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; CHECK-LABEL: @ne_max_trip_count_3
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; CHECK: Loop %for.body: max backedge-taken count is 6
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define i32 @ne_max_trip_count_3(i32 %n) {
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entry:
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%masked = and i32 %n, 7
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%guard = icmp eq i32 %masked, 0
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br i1 %guard, label %exit, label %for.preheader
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for.preheader:
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br label %for.body
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for.body:
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%i = phi i32 [ 0, %for.preheader ], [ %add, %for.body ]
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%add = add nsw i32 %i, 1
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%cmp = icmp ne i32 %add, %masked
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br i1 %cmp, label %for.body, label %loop.exit
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loop.exit:
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br label %exit
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exit:
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ret i32 0
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}
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; CHECK-LABEL: @ne_max_trip_count_4
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; CHECK: Loop %for.body: max backedge-taken count is -2
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define i32 @ne_max_trip_count_4(i32 %n) {
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entry:
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%guard = icmp eq i32 %n, 0
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br i1 %guard, label %exit, label %for.preheader
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for.preheader:
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br label %for.body
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for.body:
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%i = phi i32 [ 0, %for.preheader ], [ %add, %for.body ]
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%add = add nsw i32 %i, 1
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%cmp = icmp ne i32 %add, %n
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br i1 %cmp, label %for.body, label %loop.exit
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loop.exit:
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br label %exit
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exit:
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ret i32 0
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}
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; The end bound of the loop can change between iterations, so the exact trip
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; count is unknown, but SCEV can calculate the max trip count.
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define void @changing_end_bound(i32* %n_addr, i32* %addr) {
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; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: max backedge-taken count is 2147483646
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ 0, %entry ], [ %iv.next, %loop ]
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%acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ]
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%val = load atomic i32, i32* %addr unordered, align 4
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fence acquire
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%acc.next = add i32 %acc, %val
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%iv.next = add nsw i32 %iv, 1
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%n = load atomic i32, i32* %n_addr unordered, align 4
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%cmp = icmp slt i32 %iv.next, %n
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br i1 %cmp, label %loop, label %loop.exit
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loop.exit:
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ret void
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}
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; Similar test as above, but unknown start value.
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; Also, there's no nsw on the iv.next, but SCEV knows
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; the termination condition is LT, so the IV cannot wrap.
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define void @changing_end_bound2(i32 %start, i32* %n_addr, i32* %addr) {
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; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound2
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: max backedge-taken count is -1
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ]
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%acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ]
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%val = load atomic i32, i32* %addr unordered, align 4
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fence acquire
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%acc.next = add i32 %acc, %val
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%iv.next = add i32 %iv, 1
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%n = load atomic i32, i32* %n_addr unordered, align 4
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%cmp = icmp slt i32 %iv.next, %n
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br i1 %cmp, label %loop, label %loop.exit
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loop.exit:
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ret void
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}
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; changing end bound and greater than one stride
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define void @changing_end_bound3(i32 %start, i32* %n_addr, i32* %addr) {
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; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound3
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: max backedge-taken count is 1073741823
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ]
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%acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ]
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%val = load atomic i32, i32* %addr unordered, align 4
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fence acquire
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%acc.next = add i32 %acc, %val
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%iv.next = add nsw i32 %iv, 4
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%n = load atomic i32, i32* %n_addr unordered, align 4
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%cmp = icmp slt i32 %iv.next, %n
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br i1 %cmp, label %loop, label %loop.exit
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loop.exit:
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ret void
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}
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; same as above test, but the IV can wrap around.
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; so the max backedge taken count is unpredictable.
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define void @changing_end_bound4(i32 %start, i32* %n_addr, i32* %addr) {
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; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound4
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ]
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%acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ]
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%val = load atomic i32, i32* %addr unordered, align 4
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fence acquire
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%acc.next = add i32 %acc, %val
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%iv.next = add i32 %iv, 4
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%n = load atomic i32, i32* %n_addr unordered, align 4
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%cmp = icmp slt i32 %iv.next, %n
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br i1 %cmp, label %loop, label %loop.exit
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loop.exit:
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ret void
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}
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; unknown stride. Since it's not knownPositive, we do not estimate the max
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; backedge taken count.
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define void @changing_end_bound5(i32 %stride, i32 %start, i32* %n_addr, i32* %addr) {
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; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound5
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ]
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%acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ]
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%val = load atomic i32, i32* %addr unordered, align 4
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fence acquire
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%acc.next = add i32 %acc, %val
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%iv.next = add nsw i32 %iv, %stride
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%n = load atomic i32, i32* %n_addr unordered, align 4
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%cmp = icmp slt i32 %iv.next, %n
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br i1 %cmp, label %loop, label %loop.exit
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loop.exit:
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ret void
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}
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; negative stride value
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define void @changing_end_bound6(i32 %start, i32* %n_addr, i32* %addr) {
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; CHECK-LABEL: Determining loop execution counts for: @changing_end_bound6
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; CHECK: Loop %loop: Unpredictable backedge-taken count.
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; CHECK: Loop %loop: Unpredictable max backedge-taken count.
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entry:
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br label %loop
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loop:
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%iv = phi i32 [ %start, %entry ], [ %iv.next, %loop ]
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%acc = phi i32 [ 0, %entry ], [ %acc.next, %loop ]
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%val = load atomic i32, i32* %addr unordered, align 4
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fence acquire
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%acc.next = add i32 %acc, %val
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%iv.next = add nsw i32 %iv, -1
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%n = load atomic i32, i32* %n_addr unordered, align 4
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%cmp = icmp slt i32 %iv.next, %n
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br i1 %cmp, label %loop, label %loop.exit
|
|
|
|
loop.exit:
|
|
ret void
|
|
}
|