; RUN: opt -O2 -S < %s | FileCheck %s ; ; This test tries to ensure that simplifycfg hoisting common instructions ; of then/else branch indeed happens. BPF target has added an IR pass ; before loop optimizations as Commit 1d51dc38d89b ; ([SimplifyCFG][LoopRotate] SimplifyCFG: disable common instruction ; hoisting by default, enable late in pipeline) ; disabled common instruction hoisting. Due to optimization triggered ; code changes, later SimplifyCFG may not be able to perform optimization ; even common inst hoisting is enabled. ; ; Source: ; typedef struct { ; void *f_back; ; } FrameData; ; extern int get_data(void *, void *); ; extern void get_frame_ptr(void *); ; int test() { ; void *frame_ptr; ; FrameData frame; ; ; get_frame_ptr(&frame_ptr); ; ; #pragma nounroll ; for (int i = 0; i < 6; i++) { ; if (frame_ptr && get_data(frame_ptr, &frame)) { ; frame_ptr = frame.f_back; ; } ; } ; return frame_ptr == 0; ; } ; Compilation flag: ; clang -target bpf -O2 -Xclang -disable-llvm-passes -S -emit-llvm t.c -o t.ll target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128" target triple = "bpf" %struct.FrameData = type { i8* } ; Function Attrs: nounwind define dso_local i32 @test() #0 { entry: %frame_ptr = alloca i8*, align 8 %frame = alloca %struct.FrameData, align 8 %i = alloca i32, align 4 %0 = bitcast i8** %frame_ptr to i8* call void @llvm.lifetime.start.p0i8(i64 8, i8* %0) #3 %1 = bitcast %struct.FrameData* %frame to i8* call void @llvm.lifetime.start.p0i8(i64 8, i8* %1) #3 %2 = bitcast i8** %frame_ptr to i8* call void @get_frame_ptr(i8* %2) %3 = bitcast i32* %i to i8* call void @llvm.lifetime.start.p0i8(i64 4, i8* %3) #3 store i32 0, i32* %i, align 4, !tbaa !2 br label %for.cond ; CHECK-LABEL: entry ; CHECK: %{{[0-9]+}} = load i8*, i8** %frame_ptr, align 8 ; CHECK: %{{[0-9a-z.]+}} = icmp eq i8* %2, null ; CHECK: br label for.cond: ; preds = %for.inc, %entry %4 = load i32, i32* %i, align 4, !tbaa !2 %cmp = icmp slt i32 %4, 6 br i1 %cmp, label %for.body, label %for.cond.cleanup for.cond.cleanup: ; preds = %for.cond %5 = bitcast i32* %i to i8* call void @llvm.lifetime.end.p0i8(i64 4, i8* %5) #3 br label %for.end for.body: ; preds = %for.cond %6 = load i8*, i8** %frame_ptr, align 8, !tbaa !6 %tobool = icmp ne i8* %6, null br i1 %tobool, label %land.lhs.true, label %if.end land.lhs.true: ; preds = %for.body %7 = load i8*, i8** %frame_ptr, align 8, !tbaa !6 %8 = bitcast %struct.FrameData* %frame to i8* %call = call i32 @get_data(i8* %7, i8* %8) %tobool1 = icmp ne i32 %call, 0 br i1 %tobool1, label %if.then, label %if.end if.then: ; preds = %land.lhs.true %f_back = getelementptr inbounds %struct.FrameData, %struct.FrameData* %frame, i32 0, i32 0 %9 = load i8*, i8** %f_back, align 8, !tbaa !8 store i8* %9, i8** %frame_ptr, align 8, !tbaa !6 br label %if.end if.end: ; preds = %if.then, %land.lhs.true, %for.body br label %for.inc for.inc: ; preds = %if.end %10 = load i32, i32* %i, align 4, !tbaa !2 %inc = add nsw i32 %10, 1 store i32 %inc, i32* %i, align 4, !tbaa !2 br label %for.cond, !llvm.loop !10 for.end: ; preds = %for.cond.cleanup %11 = load i8*, i8** %frame_ptr, align 8, !tbaa !6 %cmp2 = icmp eq i8* %11, null %conv = zext i1 %cmp2 to i32 %12 = bitcast %struct.FrameData* %frame to i8* call void @llvm.lifetime.end.p0i8(i64 8, i8* %12) #3 %13 = bitcast i8** %frame_ptr to i8* call void @llvm.lifetime.end.p0i8(i64 8, i8* %13) #3 ret i32 %conv } ; Function Attrs: argmemonly nounwind willreturn declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1 declare dso_local void @get_frame_ptr(i8*) #2 declare dso_local i32 @get_data(i8*, i8*) #2 ; Function Attrs: argmemonly nounwind willreturn declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1 attributes #0 = { nounwind "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #1 = { argmemonly nounwind willreturn } attributes #2 = { "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="all" "less-precise-fpmad"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="true" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } attributes #3 = { nounwind } !llvm.module.flags = !{!0} !llvm.ident = !{!1} !0 = !{i32 1, !"wchar_size", i32 4} !1 = !{!"clang version 12.0.0 (https://github.com/llvm/llvm-project.git 1b3c1c543269da36ae41ab84f646cf98d2e5b1e5)"} !2 = !{!3, !3, i64 0} !3 = !{!"int", !4, i64 0} !4 = !{!"omnipotent char", !5, i64 0} !5 = !{!"Simple C/C++ TBAA"} !6 = !{!7, !7, i64 0} !7 = !{!"any pointer", !4, i64 0} !8 = !{!9, !7, i64 0} !9 = !{!"", !7, i64 0} !10 = distinct !{!10, !11} !11 = !{!"llvm.loop.unroll.disable"}