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[framelowering] Skip dbg values when getting next/previous instruction. 

Summary:
In mergeSPUpdates, debug values need to be ignored when getting the
previous element, otherwise debug data could have an impact on codegen.

In eliminateCallFramePseudoInstr, debug values after the erased element
could have an impact on codegen and should be skipped.

Closes PR31319 (https://llvm.org/bugs/show_bug.cgi?id=31319)

Reviewers: mkuper, MatzeB, aprantl

Subscribers: gbedwell, llvm-commits

Differential Revision: https://reviews.llvm.org/D27688

llvm-svn: 290423
This commit is contained in:
Florian Hahn 2016-12-23 11:35:00 +00:00
parent f344a51369
commit 1d6b1a7b79
3 changed files with 110 additions and 8 deletions
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5
llvm/lib/Target/X86/X86FrameLowering.cpp
View File

@ -373,6 +373,10 @@ int X86FrameLowering::mergeSPUpdates(MachineBasicBlock &MBB,
MachineBasicBlock::iterator PI = doMergeWithPrevious ? std::prev(MBBI) : MBBI;
MachineBasicBlock::iterator NI = doMergeWithPrevious ? nullptr
: std::next(MBBI);
PI = skipDebugInstructionsBackward(PI, MBB.begin());
if (NI != nullptr)
NI = skipDebugInstructionsForward(NI, MBB.end());
unsigned Opc = PI->getOpcode();
int Offset = 0;
@ -2586,6 +2590,7 @@ eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
uint64_t Amount = !reserveCallFrame ? I->getOperand(0).getImm() : 0;
uint64_t InternalAmt = (isDestroy || Amount) ? I->getOperand(1).getImm() : 0;
I = MBB.erase(I);
I = skipDebugInstructionsForward(I, MBB.end());
if (!reserveCallFrame) {
// If the stack pointer can be changed after prologue, turn the

72
llvm/test/CodeGen/X86/frame-lowering-debug-intrinsic-2.ll Normal file
View File

@ -0,0 +1,72 @@
; Test ensuring debug intrinsics do not affect generated function prologue.
;
; RUN: llc -O1 -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
@a = local_unnamed_addr global i64 0, align 8
define void @noDebug() {
entry:
%0 = load i64, i64* @a, align 8
%1 = load i64, i64* @a, align 8
%2 = load i64, i64* @a, align 8
%3 = tail call { i64, i1 } @llvm.uadd.with.overflow.i64(i64 %0, i64 %1)
%4 = extractvalue { i64, i1 } %3, 0
%5 = tail call i64 @fn1(i64 %4, i64 %2)
tail call void (...) @printf()
tail call void (...) @printf(i64 1, i64 2, i64 3, i64 4, i32 0, i64 0, i64 %4, i64 %5)
ret void
}
; CHECK-LABEL: noDebug
; CHECK: addq $24, %rsp
; CHECK: popq %rbx
; CHECK-NEXT: popq %r14
; CHECK-NEXT: retq
define void @withDebug() !dbg !18 {
entry:
%0 = load i64, i64* @a, align 8
%1 = load i64, i64* @a, align 8
%2 = load i64, i64* @a, align 8
%3 = tail call { i64, i1 } @llvm.uadd.with.overflow.i64(i64 %0, i64 %1)
%4 = extractvalue { i64, i1 } %3, 0
%5 = tail call i64 @fn1(i64 %4, i64 %2)
tail call void @llvm.dbg.value(metadata i64 %4, i64 0, metadata !23, metadata !33), !dbg !34
tail call void @llvm.dbg.value(metadata i64 %5, i64 0, metadata !22, metadata !33), !dbg !35
tail call void (...) @printf()
tail call void (...) @printf(i64 1, i64 2, i64 3, i64 4, i32 0, i64 0, i64 %4, i64 %5)
ret void
}
; CHECK-LABEL: withDebug
; CHECK: #DEBUG_VALUE: test:j <- %RBX
; CHECK-NEXT: addq $24, %rsp
; CHECK: popq %rbx
; CHECK-NEXT: popq %r14
; CHECK-NEXT: retq
declare { i64, i1 } @llvm.uadd.with.overflow.i64(i64, i64)
declare i64 @fn1(i64, i64)
declare void @printf(...)
declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
!llvm.dbg.cu = !{!1}
!llvm.module.flags = !{!15, !16}
!1 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !2, producer: "clang version 4.0.0")
!2 = !DIFile(filename: "test.cpp", directory: "")
!11 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed)
!15 = !{i32 2, !"Dwarf Version", i32 4}
!16 = !{i32 2, !"Debug Info Version", i32 3}
!18 = distinct !DISubprogram(name: "test", scope: !2, file: !2, line: 5, unit: !1)
!22 = !DILocalVariable(name: "i", scope: !18, file: !2, line: 6, type: !11)
!23 = !DILocalVariable(name: "j", scope: !18, file: !2, line: 7, type: !11)
!33 = !DIExpression()
!34 = !DILocation(line: 7, column: 17, scope: !18)
!35 = !DILocation(line: 6, column: 8, scope: !18)
!36 = !DILocation(line: 9, column: 3, scope: !18)
!37 = !DILocation(line: 10, column: 10, scope: !18)

41
llvm/test/CodeGen/X86/frame-lowering-debug-intrinsic.ll
View File

@ -2,31 +2,56 @@
;
; RUN: llc -O1 -mtriple=x86_64-unknown-unknown -o - %s | FileCheck %s
define i64 @noDebug(i64 %a) {
define i64 @fn1NoDebug(i64 %a) {
%call = call i64 @fn(i64 %a, i64 0)
ret i64 %call
}
; CHECK-LABEL: noDebug
; CHECK-LABEL: fn1NoDebug
; CHECK: popq %rcx
; CHECK: ret
; CHECK-NEXT: ret
define i64 @withDebug(i64 %a) !dbg !4 {
define i64 @fn1WithDebug(i64 %a) !dbg !4 {
%call = call i64 @fn(i64 %a, i64 0)
tail call void @llvm.dbg.value(metadata i64 %call, i64 0, metadata !5, metadata !6), !dbg !7
ret i64 %call
}
; CHECK-LABEL: withDebug
; CHECK-LABEL: fn1WithDebug
; CHECK: popq %rcx
; CHECK: ret
; CHECK-NEXT: ret
%struct.Buffer = type { i8, [63 x i8] }
define void @fn2NoDebug(%struct.Buffer* byval align 64 %p1) {
ret void
}
; CHECK-LABEL: fn2NoDebug
; CHECK: and
; CHECK-NOT: add
; CHECK-NOT: sub
; CHECK: mov
; CHECK-NEXT: pop
; CHECK-NEXT: ret
define void @fn2WithDebug(%struct.Buffer* byval align 64 %p1) !dbg !4 {
call void @llvm.dbg.declare(metadata %struct.Buffer* %p1, metadata !5, metadata !6), !dbg !7
ret void
}
; CHECK-LABEL: fn2WithDebug
; CHECK: and
; CHECK-NOT: add
; CHECK-NOT: sub
; CHECK: mov
; CHECK-NEXT: pop
; CHECK-NEXT: ret
declare i64 @fn(i64, i64)
declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
declare void @llvm.dbg.declare(metadata, metadata, metadata)
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!2,!3}