149 lines
2.7 KiB
LLVM
149 lines
2.7 KiB
LLVM
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; RUN: opt < %s -gvn -enable-pre -S | FileCheck %s
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; RUN: opt < %s -passes="gvn<pre>" -enable-pre=false -S | FileCheck %s
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declare void @may_exit() nounwind
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declare void @may_exit_1(i32) nounwind
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define i32 @main(i32 %p, i32 %q) {
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; CHECK-LABEL: @main(
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block1:
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%cmp = icmp eq i32 %p, %q
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br i1 %cmp, label %block2, label %block3
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block2:
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%a = add i32 %p, 1
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br label %block4
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block3:
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br label %block4
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; CHECK: %.pre = add i32 %p, 1
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; CHECK-NEXT: br label %block4
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block4:
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%b = add i32 %p, 1
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ret i32 %b
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; CHECK: %b.pre-phi = phi i32 [ %.pre, %block3 ], [ %a, %block2 ]
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; CHECK-NEXT: ret i32 %b.pre-phi
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}
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; Don't PRE across implicit control flow.
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define i32 @test2(i32 %p, i32 %q) {
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; CHECK-LABEL: @test2
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; CHECK: block1:
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block1:
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%cmp = icmp eq i32 %p, %q
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br i1 %cmp, label %block2, label %block3
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block2:
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%a = sdiv i32 %p, %q
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br label %block4
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block3:
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br label %block4
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; CHECK: block4:
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; CHECK-NEXT: call void @may_exit(
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; CHECK-NEXT: %b = sdiv
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; CHECK-NEXT: ret i32 %b
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block4:
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call void @may_exit() nounwind
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%b = sdiv i32 %p, %q
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ret i32 %b
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}
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; Don't PRE across implicit control flow.
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define i32 @test3(i32 %p, i32 %q, i1 %r) {
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; CHECK-LABEL: @test3
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; CHECK: block1:
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block1:
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br i1 %r, label %block2, label %block3
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block2:
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%a = sdiv i32 %p, %q
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br label %block4
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block3:
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br label %block4
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block4:
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; CHECK: block4:
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; CHECK-NEXT: phi i32
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; CHECK-NEXT: call void @may_exit_1(
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; CHECK-NEXT: %b = sdiv
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; CHECK-NEXT: ret i32 %b
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%phi = phi i32 [ 0, %block3 ], [ %a, %block2 ]
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call void @may_exit_1(i32 %phi) nounwind
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%b = sdiv i32 %p, %q
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ret i32 %b
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}
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; It's OK to PRE an instruction that is guaranteed to be safe to execute
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; speculatively.
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; TODO: Does it make any sense in this case?
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define i32 @test4(i32 %p, i32 %q) {
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; CHECK-LABEL: @test4
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; CHECK: block1:
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block1:
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%cmp = icmp eq i32 %p, %q
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br i1 %cmp, label %block2, label %block3
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block2:
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%a = sdiv i32 %p, 6
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br label %block4
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block3:
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br label %block4
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; CHECK: block4:
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; CHECK-NEXT: %b.pre-phi = phi i32
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; CHECK-NEXT: call void @may_exit(
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; CHECK-NEXT: ret i32 %b
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block4:
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call void @may_exit() nounwind
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%b = sdiv i32 %p, 6
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ret i32 %b
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}
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; It is OK to PRE across implicit control flow if we don't insert new
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; instructions.
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define i32 @test5(i1 %cond, i32 %p, i32 %q) {
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; CHECK-LABEL: @test5
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; CHECK: block1:
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block1:
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br i1 %cond, label %block2, label %block3
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block2:
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%a = sdiv i32 %p, %q
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br label %block4
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block3:
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%b = sdiv i32 %p, %q
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br label %block4
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; CHECK: block4:
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; CHECK-NEXT: %c.pre-phi = phi i32 [ %b, %block3 ], [ %a, %block2 ]
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; CHECK-NEXT: call void @may_exit()
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; CHECK-NEXT: ret i32 %c.pre-phi
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block4:
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call void @may_exit() nounwind
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%c = sdiv i32 %p, %q
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ret i32 %c
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}
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