From 899a605fc19df8f6b80f2e5e55512d04aee10c5a Mon Sep 17 00:00:00 2001 From: Ekaterina Romanova Date: Wed, 26 Mar 2014 22:15:28 +0000 Subject: This is a fix for PR# 19051. I noticed code gen differences due to code motion when running tests with and without the debug info at O2. The problem is in branch folding. A loop wanted to skip the debug info, but actually it didn't do so. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@204865 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/CodeGen/BranchFolding.cpp | 2 +- .../X86/dbg-changes-codegen-branch-folding.ll | 109 +++++++++++++++++++++ 2 files changed, 110 insertions(+), 1 deletion(-) create mode 100644 test/CodeGen/X86/dbg-changes-codegen-branch-folding.ll diff --git a/lib/CodeGen/BranchFolding.cpp b/lib/CodeGen/BranchFolding.cpp index fe8baeabc4..bf6d56ceac 100644 --- a/lib/CodeGen/BranchFolding.cpp +++ b/lib/CodeGen/BranchFolding.cpp @@ -1515,7 +1515,7 @@ MachineBasicBlock::iterator findHoistingInsertPosAndDeps(MachineBasicBlock *MBB, // branch from condition setting instruction. MachineBasicBlock::iterator PI = Loc; --PI; - while (PI != MBB->begin() && Loc->isDebugValue()) + while (PI != MBB->begin() && PI->isDebugValue()) --PI; bool IsDef = false; diff --git a/test/CodeGen/X86/dbg-changes-codegen-branch-folding.ll b/test/CodeGen/X86/dbg-changes-codegen-branch-folding.ll new file mode 100644 index 0000000000..23f83352eb --- /dev/null +++ b/test/CodeGen/X86/dbg-changes-codegen-branch-folding.ll @@ -0,0 +1,109 @@ +; RUN: llc -march=x86-64 -mtriple=x86_64-linux < %s | FileCheck %s +; RUN: opt -strip-debug < %s | llc -march=x86-64 -mtriple=x86_64-linux | FileCheck %s +; http://llvm.org/PR19051. Minor code-motion difference with -g. +; Presence of debug info shouldn't affect the codegen. Make sure that +; we generated the same code sequence with and without debug info. +; +; CHECK: callq _Z3fooPcjPKc +; CHECK: callq _Z3fooPcjPKc +; CHECK: leaq (%rsp), %rdi +; CHECK: movl $4, %esi +; CHECK: testl {{%[a-z]+}}, {{%[a-z]+}} +; CHECK: je .LBB0_4 + +; Regenerate test with this command: +; clang -emit-llvm -S -O2 -g +; from this source: +; +; extern void foo(char *dst,unsigned siz,const char *src); +; extern const char * i2str(int); +; +; struct AAA3 { +; AAA3(const char *value) { foo(text,sizeof(text),value);} +; void operator=(const char *value) { foo(text,sizeof(text),value);} +; operator const char*() const { return text;} +; char text[4]; +; }; +; +; void bar (int param1,int param2) { +; const char * temp(0); +; +; if (param2) { +; temp = i2str(param2); +; } +; AAA3 var1(""); +; AAA3 var2(""); +; +; if (param1) +; var2 = "+"; +; else +; var2 = "-"; +; var1 = ""; +; } + +%struct.AAA3 = type { [4 x i8] } + +@.str = private unnamed_addr constant [1 x i8] zeroinitializer, align 1 +@.str1 = private unnamed_addr constant [2 x i8] c"+\00", align 1 +@.str2 = private unnamed_addr constant [2 x i8] c"-\00", align 1 + +; Function Attrs: uwtable +define void @_Z3barii(i32 %param1, i32 %param2) #0 { +entry: + %var1 = alloca %struct.AAA3, align 1 + %var2 = alloca %struct.AAA3, align 1 + %tobool = icmp eq i32 %param2, 0 + br i1 %tobool, label %if.end, label %if.then + +if.then: ; preds = %entry + %call = call i8* @_Z5i2stri(i32 %param2) + br label %if.end + +if.end: ; preds = %entry, %if.then + call void @llvm.dbg.value(metadata !{%struct.AAA3* %var1}, i64 0, metadata !60) + call void @llvm.dbg.value(metadata !62, i64 0, metadata !63) + %arraydecay.i = getelementptr inbounds %struct.AAA3* %var1, i64 0, i32 0, i64 0 + call void @_Z3fooPcjPKc(i8* %arraydecay.i, i32 4, i8* getelementptr inbounds ([1 x i8]* @.str, i64 0, i64 0)) + call void @llvm.dbg.declare(metadata !{%struct.AAA3* %var2}, metadata !38) + %arraydecay.i5 = getelementptr inbounds %struct.AAA3* %var2, i64 0, i32 0, i64 0 + call void @_Z3fooPcjPKc(i8* %arraydecay.i5, i32 4, i8* getelementptr inbounds ([1 x i8]* @.str, i64 0, i64 0)) + %tobool1 = icmp eq i32 %param1, 0 + br i1 %tobool1, label %if.else, label %if.then2 + +if.then2: ; preds = %if.end + call void @_Z3fooPcjPKc(i8* %arraydecay.i5, i32 4, i8* getelementptr inbounds ([2 x i8]* @.str1, i64 0, i64 0)) + br label %if.end3 + +if.else: ; preds = %if.end + call void @_Z3fooPcjPKc(i8* %arraydecay.i5, i32 4, i8* getelementptr inbounds ([2 x i8]* @.str2, i64 0, i64 0)) + br label %if.end3 + +if.end3: ; preds = %if.else, %if.then2 + call void @_Z3fooPcjPKc(i8* %arraydecay.i, i32 4, i8* getelementptr inbounds ([1 x i8]* @.str, i64 0, i64 0)) + ret void +} + +; Function Attrs: nounwind readnone +declare void @llvm.dbg.declare(metadata, metadata) #1 + +declare i8* @_Z5i2stri(i32) #2 + +declare void @_Z3fooPcjPKc(i8*, i32, i8*) #2 + +; Function Attrs: nounwind readnone +declare void @llvm.dbg.value(metadata, i64, metadata) #1 + +attributes #0 = { uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } +attributes #1 = { nounwind readnone } +attributes #2 = { "less-precise-fpmad"="false" "no-frame-pointer-elim"="false" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" } + +!llvm.module.flags = !{!48, !49} +!llvm.ident = !{!50} + +!38 = metadata !{i32 786688, null, metadata !"var2", null, i32 20, null, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [var2] [line 20] +!48 = metadata !{i32 2, metadata !"Dwarf Version", i32 4} +!49 = metadata !{i32 1, metadata !"Debug Info Version", i32 1} +!50 = metadata !{metadata !"clang version 3.5 (202418)"} +!60 = metadata !{i32 786689, null, metadata !"this", null, i32 16777216, null, i32 1088, null} ; [ DW_TAG_arg_variable ] [this] [line 0] +!62 = metadata !{i8* getelementptr inbounds ([1 x i8]* @.str, i64 0, i64 0)} +!63 = metadata !{i32 786689, null, metadata !"value", null, i32 33554439, null, i32 0, null} ; [ DW_TAG_arg_variable ] [value] [line 7] -- cgit v1.2.3