; RUN: opt --bpf-ir-peephole -mtriple=bpf-pc-linux -S %s | FileCheck %s ; Source: ; #define AA 40 ; struct t { ; char a[20]; ; }; ; void foo(void *); ; ; int test1() { ; const int a = 8; ; char tmp[AA + sizeof(struct t) + a]; ; foo(tmp); ; return 0; ; } ; ; int test2(int b) { ; const int a = 8; ; char tmp[a + b]; ; foo(tmp); ; return 0; ; } ; Compilation flag: ; clang -target bpf -O2 -S -emit-llvm t.c -Xclang -disable-llvm-passes source_filename = "t.c" target datalayout = "e-m:e-p:64:64-i64:64-i128:128-n32:64-S128" target triple = "bpf" ; Function Attrs: nounwind define dso_local i32 @test1() #0 { entry: %a = alloca i32, align 4 %saved_stack = alloca i8*, align 8 %0 = bitcast i32* %a to i8* call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #4 store i32 8, i32* %a, align 4, !tbaa !3 %1 = call i8* @llvm.stacksave() store i8* %1, i8** %saved_stack, align 8 %vla = alloca i8, i64 68, align 1 call void @foo(i8* %vla) %2 = load i8*, i8** %saved_stack, align 8 call void @llvm.stackrestore(i8* %2) %3 = bitcast i32* %a to i8* call void @llvm.lifetime.end.p0i8(i64 4, i8* %3) #4 ret i32 0 } ; CHECK: define dso_local i32 @test1 ; CHECK-NOT: %[[#]] = call i8* @llvm.stacksave() ; CHECK-NOT: store i8* %[[#]], i8** %saved_stack, align 8 ; CHECK-NOT: %[[#]] = load i8*, i8** %saved_stack, align 8 ; CHECK-NOT: call void @llvm.stackrestore(i8* %[[#]]) ; Function Attrs: argmemonly nofree nosync nounwind willreturn declare void @llvm.lifetime.start.p0i8(i64 immarg, i8* nocapture) #1 ; Function Attrs: nofree nosync nounwind willreturn declare i8* @llvm.stacksave() #2 declare dso_local void @foo(i8*) #3 ; Function Attrs: nofree nosync nounwind willreturn declare void @llvm.stackrestore(i8*) #2 ; Function Attrs: argmemonly nofree nosync nounwind willreturn declare void @llvm.lifetime.end.p0i8(i64 immarg, i8* nocapture) #1 ; Function Attrs: nounwind define dso_local i32 @test2(i32 %b) #0 { entry: %b.addr = alloca i32, align 4 %a = alloca i32, align 4 %saved_stack = alloca i8*, align 8 %__vla_expr0 = alloca i64, align 8 store i32 %b, i32* %b.addr, align 4, !tbaa !3 %0 = bitcast i32* %a to i8* call void @llvm.lifetime.start.p0i8(i64 4, i8* %0) #4 store i32 8, i32* %a, align 4, !tbaa !3 %1 = load i32, i32* %b.addr, align 4, !tbaa !3 %add = add nsw i32 8, %1 %2 = zext i32 %add to i64 %3 = call i8* @llvm.stacksave() store i8* %3, i8** %saved_stack, align 8 %vla = alloca i8, i64 %2, align 1 store i64 %2, i64* %__vla_expr0, align 8 call void @foo(i8* %vla) %4 = load i8*, i8** %saved_stack, align 8 call void @llvm.stackrestore(i8* %4) %5 = bitcast i32* %a to i8* call void @llvm.lifetime.end.p0i8(i64 4, i8* %5) #4 ret i32 0 } ; CHECK: define dso_local i32 @test2 ; CHECK-NOT: %[[#]] = call i8* @llvm.stacksave() ; CHECK-NOT: store i8* %[[#]], i8** %saved_stack, align 8 ; CHECK-NOT: %[[#]] = load i8*, i8** %saved_stack, align 8 ; CHECK-NOT: call void @llvm.stackrestore(i8* %[[#]]) attributes #0 = { nounwind "frame-pointer"="all" "min-legal-vector-width"="0" "no-trapping-math"="true" "stack-protector-buffer-size"="8" } attributes #1 = { argmemonly nofree nosync nounwind willreturn } attributes #2 = { nofree nosync nounwind willreturn } attributes #3 = { "frame-pointer"="all" "no-trapping-math"="true" "stack-protector-buffer-size"="8" } attributes #4 = { nounwind } !llvm.module.flags = !{!0, !1} !llvm.ident = !{!2} !0 = !{i32 1, !"wchar_size", i32 4} !1 = !{i32 7, !"frame-pointer", i32 2} !2 = !{!"clang version 14.0.0 (https://github.com/llvm/llvm-project.git 64c5d5c671fb5b5f25c464652a4eec2cf743af0d)"} !3 = !{!4, !4, i64 0} !4 = !{!"int", !5, i64 0} !5 = !{!"omnipotent char", !6, i64 0} !6 = !{!"Simple C/C++ TBAA"}