/// If SafetyInfo is not null, we are checking for hoisting/sinking
/// instructions from loop body to preheader/exit. Check if the instruction
/// can execute speculatively.
-///
+/// If \p ORE is set use it to emit optimization remarks.
bool canSinkOrHoistInst(Instruction &I, AAResults *AA, DominatorTree *DT,
Loop *CurLoop, AliasSetTracker *CurAST,
- LoopSafetyInfo *SafetyInfo);
+ LoopSafetyInfo *SafetyInfo,
+ OptimizationRemarkEmitter *ORE = nullptr);
}
#endif
// operands of the instruction are loop invariant.
//
if (isNotUsedInLoop(I, CurLoop, SafetyInfo) &&
- canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, SafetyInfo)) {
+ canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, SafetyInfo, ORE)) {
++II;
Changed |= sink(I, LI, DT, CurLoop, CurAST, SafetyInfo, ORE);
}
// is safe to hoist the instruction.
//
if (CurLoop->hasLoopInvariantOperands(&I) &&
- canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, SafetyInfo) &&
+ canSinkOrHoistInst(I, AA, DT, CurLoop, CurAST, SafetyInfo, ORE) &&
isSafeToExecuteUnconditionally(
I, DT, CurLoop, SafetyInfo,
CurLoop->getLoopPreheader()->getTerminator()))
bool llvm::canSinkOrHoistInst(Instruction &I, AAResults *AA, DominatorTree *DT,
Loop *CurLoop, AliasSetTracker *CurAST,
- LoopSafetyInfo *SafetyInfo) {
+ LoopSafetyInfo *SafetyInfo,
+ OptimizationRemarkEmitter *ORE) {
// Loads have extra constraints we have to verify before we can hoist them.
if (LoadInst *LI = dyn_cast<LoadInst>(&I)) {
if (!LI->isUnordered())
AAMDNodes AAInfo;
LI->getAAMetadata(AAInfo);
- return !pointerInvalidatedByLoop(LI->getOperand(0), Size, AAInfo, CurAST);
+ bool Invalidated =
+ pointerInvalidatedByLoop(LI->getOperand(0), Size, AAInfo, CurAST);
+ // Check loop-invariant address because this may also be a sinkable load
+ // whose address is not necessarily loop-invariant.
+ if (ORE && Invalidated && CurLoop->isLoopInvariant(LI->getPointerOperand()))
+ ORE->emit(OptimizationRemarkMissed(
+ DEBUG_TYPE, "LoadWithLoopInvariantAddressInvalidated", LI)
+ << "failed to move load with loop-invariant address "
+ "because the loop may invalidate its value");
+
+ return !Invalidated;
} else if (CallInst *CI = dyn_cast<CallInst>(&I)) {
// Don't sink or hoist dbg info; it's legal, but not useful.
if (isa<DbgInfoIntrinsic>(I))
--- /dev/null
+; RUN: opt < %s -licm -pass-remarks-missed=licm -o /dev/null 2>&1 | FileCheck %s
+; RUN: opt -aa-pipeline=basic-aa -passes='require<aa>,require<targetir>,require<scalar-evolution>,require<opt-remark-emit>,loop(licm)' %s -o /dev/null -pass-remarks-missed=licm 2>&1 | FileCheck %s
+target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
+
+; Without the noalias on %p, we can't optmize this and the remark should tell
+; us about it.
+
+define void @test(i32* %array, i32* %p) {
+Entry:
+ br label %Loop
+
+Loop:
+ %j = phi i32 [ 0, %Entry ], [ %Next, %Loop ]
+ %addr = getelementptr i32, i32* %array, i32 %j
+ %a = load i32, i32* %addr
+; CHECK: remark: /tmp/kk.c:2:20: failed to move load with loop-invariant address because the loop may invalidate its value
+ %b = load i32, i32* %p, !dbg !8
+ %a2 = add i32 %a, %b
+ store i32 %a2, i32* %addr
+ %Next = add i32 %j, 1
+ %cond = icmp eq i32 %Next, 0
+ br i1 %cond, label %Out, label %Loop
+
+Out:
+ ret void
+}
+
+; This illustrates why we need to check loop-invariance before issuing this
+; remark.
+
+define i32 @invalidated_load_with_non_loop_invariant_address(i32* %array, i32* %array2) {
+Entry:
+ br label %Loop
+
+Loop:
+ %j = phi i32 [ 0, %Entry ], [ %Next, %Loop ]
+
+; CHECK-NOT: /tmp/kk.c:3:20: {{.*}} loop-invariant
+ %addr = getelementptr i32, i32* %array, i32 %j
+ %a = load i32, i32* %addr, !dbg !9
+
+ %addr2 = getelementptr i32, i32* %array2, i32 %j
+ store i32 %j, i32* %addr2
+
+ %Next = add i32 %j, 1
+ %cond = icmp eq i32 %Next, 0
+ br i1 %cond, label %Out, label %Loop
+
+Out:
+ %a2 = phi i32 [ %a, %Loop ]
+ ret i32 %a2
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4}
+!llvm.ident = !{!5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 ", isOptimized: true, runtimeVersion: 0, emissionKind: NoDebug, enums: !2)
+!1 = !DIFile(filename: "/tmp/kk.c", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"PIC Level", i32 2}
+!5 = !{!"clang version 3.9.0 "}
+!6 = distinct !DISubprogram(name: "success", scope: !1, file: !1, line: 1, type: !7, isLocal: false, isDefinition: true, scopeLine: 1, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !2)
+!7 = !DISubroutineType(types: !2)
+!8 = !DILocation(line: 2, column: 20, scope: !6)
+!9 = !DILocation(line: 3, column: 20, scope: !6)