llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-llvm-transforms Author: None (llvmbot) <details> <summary>Changes</summary> resolves llvm/llvm-project#<!-- -->79861 --- Full diff: https://github.com/llvm/llvm-project/pull/80832.diff 4 Files Affected: - (modified) llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp (+7) - (modified) llvm/lib/Transforms/Utils/SimplifyIndVar.cpp (+16-2) - (modified) llvm/test/Transforms/IndVarSimplify/pr55925.ll (+2-2) - (added) llvm/test/Transforms/IndVarSimplify/pr79861.ll (+107) ``````````diff diff --git a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp index a1d7f0f9ba0f7..e6f93e72c98a7 100644 --- a/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp +++ b/llvm/lib/Transforms/Utils/ScalarEvolutionExpander.cpp @@ -1401,6 +1401,13 @@ canReuseInstruction(ScalarEvolution &SE, const SCEV *S, Instruction *I, if (!I) return false; + // Disjoint or instructions are interpreted as adds by SCEV. However, we + // can't replace an arbitrary add with disjoint or, even if we drop the + // flag. We would need to convert the or into an add. + if (auto *PDI = dyn_cast<PossiblyDisjointInst>(I)) + if (PDI->isDisjoint()) + return false; + // FIXME: Ignore vscale, even though it technically could be poison. Do this // because SCEV currently assumes it can't be poison. Remove this special // case once we proper model when vscale can be poison. diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp index 0ed3324a27b6c..1b142f14d8113 100644 --- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp @@ -16,6 +16,7 @@ #include "llvm/ADT/SmallVector.h" #include "llvm/ADT/Statistic.h" #include "llvm/Analysis/LoopInfo.h" +#include "llvm/Analysis/ValueTracking.h" #include "llvm/IR/Dominators.h" #include "llvm/IR/IRBuilder.h" #include "llvm/IR/Instructions.h" @@ -713,8 +714,11 @@ bool SimplifyIndvar::replaceFloatIVWithIntegerIV(Instruction *UseInst) { bool SimplifyIndvar::eliminateIdentitySCEV(Instruction *UseInst, Instruction *IVOperand) { if (!SE->isSCEVable(UseInst->getType()) || - (UseInst->getType() != IVOperand->getType()) || - (SE->getSCEV(UseInst) != SE->getSCEV(IVOperand))) + UseInst->getType() != IVOperand->getType()) + return false; + + const SCEV *UseSCEV = SE->getSCEV(UseInst); + if (UseSCEV != SE->getSCEV(IVOperand)) return false; // getSCEV(X) == getSCEV(Y) does not guarantee that X and Y are related in the @@ -742,6 +746,16 @@ bool SimplifyIndvar::eliminateIdentitySCEV(Instruction *UseInst, if (!LI->replacementPreservesLCSSAForm(UseInst, IVOperand)) return false; + // Make sure the operand is not more poisonous than the instruction. + if (!impliesPoison(IVOperand, UseInst)) { + SmallVector<Instruction *> DropPoisonGeneratingInsts; + if (!SE->canReuseInstruction(UseSCEV, IVOperand, DropPoisonGeneratingInsts)) + return false; + + for (Instruction *I : DropPoisonGeneratingInsts) + I->dropPoisonGeneratingFlagsAndMetadata(); + } + LLVM_DEBUG(dbgs() << "INDVARS: Eliminated identity: " << *UseInst << '\n'); SE->forgetValue(UseInst); diff --git a/llvm/test/Transforms/IndVarSimplify/pr55925.ll b/llvm/test/Transforms/IndVarSimplify/pr55925.ll index 420fc209949d4..312a8295ccdc9 100644 --- a/llvm/test/Transforms/IndVarSimplify/pr55925.ll +++ b/llvm/test/Transforms/IndVarSimplify/pr55925.ll @@ -18,9 +18,9 @@ define void @test(ptr %p) personality ptr undef { ; CHECK-NEXT: [[RES:%.*]] = invoke i32 @foo(i32 returned [[TMP0]]) ; CHECK-NEXT: to label [[LOOP_LATCH]] unwind label [[EXIT:%.*]] ; CHECK: loop.latch: -; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: [[TMP1:%.*]] = trunc i64 [[INDVARS_IV]] to i32 ; CHECK-NEXT: [[TMP2:%.*]] = call i32 @foo(i32 [[TMP1]]) +; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: br label [[LOOP]] ; CHECK: exit: ; CHECK-NEXT: [[LP:%.*]] = landingpad { ptr, i32 } @@ -64,8 +64,8 @@ define void @test_critedge(i1 %c, ptr %p) personality ptr undef { ; CHECK-NEXT: br label [[LOOP_LATCH]] ; CHECK: loop.latch: ; CHECK-NEXT: [[PHI:%.*]] = phi i32 [ [[TMP1]], [[LOOP_INVOKE]] ], [ 0, [[LOOP_OTHER]] ] -; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: [[TMP2:%.*]] = call i32 @foo(i32 [[PHI]]) +; CHECK-NEXT: [[INDVARS_IV_NEXT]] = add i64 [[INDVARS_IV]], 1 ; CHECK-NEXT: br label [[LOOP]] ; CHECK: exit: ; CHECK-NEXT: [[LP:%.*]] = landingpad { ptr, i32 } diff --git a/llvm/test/Transforms/IndVarSimplify/pr79861.ll b/llvm/test/Transforms/IndVarSimplify/pr79861.ll new file mode 100644 index 0000000000000..6625094496139 --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/pr79861.ll @@ -0,0 +1,107 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 4 +; RUN: opt -S -passes=indvars < %s | FileCheck %s + +target datalayout = "n64" + +declare void @use(i64) + +define void @or_disjoint() { +; CHECK-LABEL: define void @or_disjoint() { +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 2, [[ENTRY:%.*]] ], [ [[IV_DEC:%.*]], [[LOOP]] ] +; CHECK-NEXT: [[OR:%.*]] = or disjoint i64 [[IV]], 1 +; CHECK-NEXT: [[ADD:%.*]] = add nuw nsw i64 [[IV]], 1 +; CHECK-NEXT: [[SEL:%.*]] = select i1 false, i64 [[OR]], i64 [[ADD]] +; CHECK-NEXT: call void @use(i64 [[SEL]]) +; CHECK-NEXT: [[IV_DEC]] = add nsw i64 [[IV]], -1 +; CHECK-NEXT: [[EXIT_COND:%.*]] = icmp eq i64 [[IV_DEC]], 0 +; CHECK-NEXT: br i1 [[EXIT_COND]], label [[EXIT:%.*]], label [[LOOP]] +; CHECK: exit: +; CHECK-NEXT: ret void +; +entry: + br label %loop + +loop: + %iv = phi i64 [ 2, %entry ], [ %iv.dec, %loop ] + %or = or disjoint i64 %iv, 1 + %add = add nsw i64 %iv, 1 + %sel = select i1 false, i64 %or, i64 %add + call void @use(i64 %sel) + + %iv.dec = add nsw i64 %iv, -1 + %exit.cond = icmp eq i64 %iv.dec, 0 + br i1 %exit.cond, label %exit, label %loop + +exit: + ret void +} + +define void @add_nowrap_flags(i64 %n) { +; CHECK-LABEL: define void @add_nowrap_flags( +; CHECK-SAME: i64 [[N:%.*]]) { +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[LOOP]] ] +; CHECK-NEXT: [[ADD1:%.*]] = add i64 [[IV]], 123 +; CHECK-NEXT: call void @use(i64 [[ADD1]]) +; CHECK-NEXT: [[IV_INC]] = add i64 [[IV]], 1 +; CHECK-NEXT: [[EXIT_COND:%.*]] = icmp eq i64 [[IV_INC]], [[N]] +; CHECK-NEXT: br i1 [[EXIT_COND]], label [[EXIT:%.*]], label [[LOOP]] +; CHECK: exit: +; CHECK-NEXT: ret void +; +entry: + br label %loop + +loop: + %iv = phi i64 [ 0, %entry ], [ %iv.inc, %loop ] + %add1 = add nuw nsw i64 %iv, 123 + %add2 = add i64 %iv, 123 + %sel = select i1 false, i64 %add1, i64 %add2 + call void @use(i64 %sel) + + %iv.inc = add i64 %iv, 1 + %exit.cond = icmp eq i64 %iv.inc, %n + br i1 %exit.cond, label %exit, label %loop + +exit: + ret void +} + + +define void @expander_or_disjoint(i64 %n) { +; CHECK-LABEL: define void @expander_or_disjoint( +; CHECK-SAME: i64 [[N:%.*]]) { +; CHECK-NEXT: entry: +; CHECK-NEXT: [[OR:%.*]] = or disjoint i64 [[N]], 1 +; CHECK-NEXT: [[TMP0:%.*]] = add i64 [[N]], 1 +; CHECK-NEXT: br label [[LOOP:%.*]] +; CHECK: loop: +; CHECK-NEXT: [[IV:%.*]] = phi i64 [ 0, [[ENTRY:%.*]] ], [ [[IV_INC:%.*]], [[LOOP]] ] +; CHECK-NEXT: [[IV_INC]] = add i64 [[IV]], 1 +; CHECK-NEXT: [[ADD:%.*]] = add i64 [[IV]], [[OR]] +; CHECK-NEXT: call void @use(i64 [[ADD]]) +; CHECK-NEXT: [[EXITCOND:%.*]] = icmp ne i64 [[IV_INC]], [[TMP0]] +; CHECK-NEXT: br i1 [[EXITCOND]], label [[LOOP]], label [[EXIT:%.*]] +; CHECK: exit: +; CHECK-NEXT: ret void +; +entry: + %or = or disjoint i64 %n, 1 + br label %loop + +loop: + %iv = phi i64 [ 0, %entry ], [ %iv.inc, %loop ] + %iv.inc = add i64 %iv, 1 + %add = add i64 %iv, %or + call void @use(i64 %add) + %cmp = icmp ult i64 %iv, %n + br i1 %cmp, label %loop, label %exit + +exit: + ret void +} `````````` </details> https://github.com/llvm/llvm-project/pull/80832 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits