replica
/
hanchenye-llvm-project
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

Revert "[GVN, OptDiag] Print the interesting instructions involved in missed load-elimination" 

This reverts commit r288090.

Trying to see if the revert fixes a compiler crash during a stage2 LTO
build with a GVN backtrace.

llvm-svn: 288177
This commit is contained in:
Adam Nemet 2016-11-29 18:31:53 +00:00
parent 7c078fc035
commit a4d3d44ec2
3 changed files with 2 additions and 94 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
llvm/include/llvm/Analysis/OptimizationDiagnosticInfo.h
View File

@ -18,12 +18,12 @@
#include "llvm/ADT/Optional.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/PassManager.h"
#include "llvm/Pass.h"
namespace llvm {
class DebugLoc;
class Function;
class LLVMContext;
class Loop;
class Pass;
@ -194,19 +194,6 @@ public:
void emitOptimizationRemarkAnalysisAliasing(const char *PassName, Loop *L,
const Twine &Msg);
/// \brief Whether we allow for extra compile-time budget to perform more
/// analysis to produce fewer false positives.
///
/// This is useful when reporting missed optimizations. In this case we can
/// use the extra analysis (1) to filter trivial false positives or (2) to
/// provide more context so that non-trivial false positives can be quickly
/// detected by the user.
bool allowExtraAnalysis() const {
// For now, only allow this with -fsave-optimization-record since the -Rpass
// options are handled in the front-end.
return F->getContext().getDiagnosticsOutputFile();
}
private:
Function *F;

36
llvm/lib/Transforms/Scalar/GVN.cpp
View File

@ -1208,38 +1208,6 @@ static bool isLifetimeStart(const Instruction *Inst) {
return false;
}
/// \brief Try to locate the three instruction involved in a missed
/// load-elimination case that is due to an intervening store.
static void reportMayClobberedLoad(LoadInst *LI, MemDepResult DepInfo,
DominatorTree *DT,
OptimizationRemarkEmitter *ORE) {
using namespace ore;
User *OtherAccess = nullptr;
OptimizationRemarkMissed R(DEBUG_TYPE, "LoadClobbered", LI);
R << "load of type " << NV("Type", LI->getType()) << " not eliminated"
<< setExtraArgs();
for (auto *U : LI->getPointerOperand()->users())
if (U != LI && (isa<LoadInst>(U) || isa<StoreInst>(U)) &&
DT->dominates(cast<Instruction>(U), LI)) {
// FIXME: for now give up if there are multiple memory accesses that
// dominate the load. We need further analysis to decide which one is
// that we're forwarding from.
if (OtherAccess)
OtherAccess = nullptr;
else
OtherAccess = U;
}
if (OtherAccess)
R << " in favor of " << NV("OtherAccess", OtherAccess);
R << " because it is clobbered by " << NV("ClobberedBy", DepInfo.getInst());
ORE->emit(R);
}
bool GVN::AnalyzeLoadAvailability(LoadInst *LI, MemDepResult DepInfo,
Value *Address, AvailableValue &Res) {
@ -1304,10 +1272,6 @@ bool GVN::AnalyzeLoadAvailability(LoadInst *LI, MemDepResult DepInfo,
Instruction *I = DepInfo.getInst();
dbgs() << " is clobbered by " << *I << '\n';
);
if (ORE->allowExtraAnalysis())
reportMayClobberedLoad(LI, DepInfo, DT, ORE);
return false;
}
assert(DepInfo.isDef() && "follows from above");

45
llvm/test/Transforms/GVN/opt-remarks.ll
View File

@ -40,22 +40,7 @@
; YAML-NEXT: - String: ' in favor of '
; YAML-NEXT: - InfavorOfValue: load
; YAML-NEXT: ...
; YAML-NEXT: --- !Missed
; YAML-NEXT: Pass: gvn
; YAML-NEXT: Name: LoadClobbered
; YAML-NEXT: DebugLoc: { File: /tmp/s.c, Line: 3, Column: 3 }
; YAML-NEXT: Function: may_alias
; YAML-NEXT: Args:
; YAML-NEXT: - String: 'load of type '
; YAML-NEXT: - Type: i32
; YAML-NEXT: - String: ' not eliminated'
; YAML-NEXT: - String: ' in favor of '
; YAML-NEXT: - OtherAccess: load
; YAML-NEXT: DebugLoc: { File: /tmp/s.c, Line: 1, Column: 13 }
; YAML-NEXT: - String: ' because it is clobbered by '
; YAML-NEXT: - ClobberedBy: store
; YAML-NEXT: DebugLoc: { File: /tmp/s.c, Line: 2, Column: 10 }
; YAML-NEXT: ...
define i32 @arg(i32* %p, i32 %i) {
entry:
@ -78,31 +63,3 @@ entry:
%add = add i32 %load1, %load
ret i32 %add
}
define i32 @may_alias(i32* %p, i32* %r) !dbg !7 {
entry:
%load1 = load i32, i32* %p, !tbaa !13, !dbg !9
store i32 4, i32* %r, !tbaa !13, !dbg !10
%load = load i32, i32* %p, !tbaa !13, !dbg !11
%add = add i32 %load1, %load
ret i32 %add
}
!llvm.dbg.cu = !{!0}
!llvm.module.flags = !{!3, !4, !5}
!llvm.ident = !{!6}
!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 4.0.0 (trunk 282540) (llvm/trunk 282542)", isOptimized: true, runtimeVersion: 0, emissionKind: LineTablesOnly, enums: !2)
!1 = !DIFile(filename: "/tmp/s.c", directory: "/tmp")
!2 = !{}
!3 = !{i32 2, !"Dwarf Version", i32 4}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = !{i32 1, !"PIC Level", i32 2}
!6 = !{!"clang version 4.0.0 (trunk 282540) (llvm/trunk 282542)"}
!7 = distinct !DISubprogram(name: "may_alias", scope: !1, file: !1, line: 1, type: !8, isLocal: false, isDefinition: true, scopeLine: 1, isOptimized: true, unit: !0, variables: !2)
!8 = !DISubroutineType(types: !2)
!9 = !DILocation(line: 1, column: 13, scope: !7)
!10 = !DILocation(line: 2, column: 10, scope: !7)
!11 = !DILocation(line: 3, column: 3, scope: !7)
!12 = !{ !"tbaa root" }
!13 = !{ !"int", !12 }