diff --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp index 84ee8c0bf3e18..5573c0abb5c92 100644 --- a/llvm/lib/Analysis/DependenceAnalysis.cpp +++ b/llvm/lib/Analysis/DependenceAnalysis.cpp @@ -1587,6 +1587,15 @@ static const SCEV *minusSCEVNoSignedOverflow(const SCEV *A, const SCEV *B, return nullptr; } +/// Returns \p A * \p B if it guaranteed not to signed wrap. Otherwise returns +/// nullptr. \p A and \p B must have the same integer type. +static const SCEV *mulSCEVNoSignedOverflow(const SCEV *A, const SCEV *B, + ScalarEvolution &SE) { + if (SE.willNotOverflow(Instruction::Mul, /*Signed=*/true, A, B)) + return SE.getMulExpr(A, B); + return nullptr; +} + /// Returns the absolute value of \p A. In the context of dependence analysis, /// we need an absolute value in a mathematical sense. If \p A is the signed /// minimum value, we cannot represent it unless extending the original type. @@ -1686,7 +1695,11 @@ bool DependenceInfo::strongSIVtest(const SCEV *Coeff, const SCEV *SrcConst, assert(0 < Level && Level <= CommonLevels && "level out of range"); Level--; - const SCEV *Delta = SE->getMinusSCEV(SrcConst, DstConst); + const SCEV *Delta = minusSCEVNoSignedOverflow(SrcConst, DstConst, *SE); + if (!Delta) { + Result.Consistent = false; + return false; + } LLVM_DEBUG(dbgs() << "\t Delta = " << *Delta); LLVM_DEBUG(dbgs() << ", " << *Delta->getType() << "\n"); @@ -1702,7 +1715,9 @@ bool DependenceInfo::strongSIVtest(const SCEV *Coeff, const SCEV *SrcConst, const SCEV *AbsCoeff = absSCEVNoSignedOverflow(Coeff, *SE); if (!AbsDelta || !AbsCoeff) return false; - const SCEV *Product = SE->getMulExpr(UpperBound, AbsCoeff); + const SCEV *Product = mulSCEVNoSignedOverflow(UpperBound, AbsCoeff, *SE); + if (!Product) + return false; return isKnownPredicate(CmpInst::ICMP_SGT, AbsDelta, Product); }(); if (IsDeltaLarge) { diff --git a/llvm/test/Analysis/DependenceAnalysis/SimpleSIVNoValidityCheck.ll b/llvm/test/Analysis/DependenceAnalysis/SimpleSIVNoValidityCheck.ll index 4346507ba8f90..181a4494b036e 100644 --- a/llvm/test/Analysis/DependenceAnalysis/SimpleSIVNoValidityCheck.ll +++ b/llvm/test/Analysis/DependenceAnalysis/SimpleSIVNoValidityCheck.ll @@ -210,7 +210,7 @@ define void @t3(i64 %n, i64 %m, i64 %lb, ptr %a) { ; CHECK-NEXT: Src: %2 = load i32, ptr %arrayidx6, align 4 --> Dst: %2 = load i32, ptr %arrayidx6, align 4 ; CHECK-NEXT: da analyze - none! ; CHECK-NEXT: Src: %2 = load i32, ptr %arrayidx6, align 4 --> Dst: store i32 %2, ptr %arrayidx8, align 4 -; CHECK-NEXT: da analyze - consistent anti [1 -2]! +; CHECK-NEXT: da analyze - anti [1 *]! ; CHECK-NEXT: Src: store i32 %2, ptr %arrayidx8, align 4 --> Dst: store i32 %2, ptr %arrayidx8, align 4 ; CHECK-NEXT: da analyze - none! ; diff --git a/llvm/test/Analysis/DependenceAnalysis/StrongSIV.ll b/llvm/test/Analysis/DependenceAnalysis/StrongSIV.ll index 44bd9b7727910..160196284f415 100644 --- a/llvm/test/Analysis/DependenceAnalysis/StrongSIV.ll +++ b/llvm/test/Analysis/DependenceAnalysis/StrongSIV.ll @@ -1,6 +1,8 @@ ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5 ; RUN: opt < %s -disable-output "-passes=print" -aa-pipeline=basic-aa 2>&1 \ -; RUN: | FileCheck %s +; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-ALL +; RUN: opt < %s -disable-output "-passes=print" -aa-pipeline=basic-aa -da-enable-dependence-test=strong-siv 2>&1 \ +; RUN: | FileCheck %s --check-prefixes=CHECK,CHECK-STRONG-SIV target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128" target triple = "x86_64-apple-macosx10.6.0" @@ -423,19 +425,33 @@ for.end: ; preds = %for.body ;; *B++ = A[i + 2*n]; define void @strong9(ptr %A, ptr %B, i64 %n) nounwind uwtable ssp { -; CHECK-LABEL: 'strong9' -; CHECK-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: store i32 %conv, ptr %arrayidx, align 4 -; CHECK-NEXT: da analyze - none! -; CHECK-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: %0 = load i32, ptr %arrayidx2, align 4 -; CHECK-NEXT: da analyze - none! -; CHECK-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 -; CHECK-NEXT: da analyze - confused! -; CHECK-NEXT: Src: %0 = load i32, ptr %arrayidx2, align 4 --> Dst: %0 = load i32, ptr %arrayidx2, align 4 -; CHECK-NEXT: da analyze - none! -; CHECK-NEXT: Src: %0 = load i32, ptr %arrayidx2, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 -; CHECK-NEXT: da analyze - confused! -; CHECK-NEXT: Src: store i32 %0, ptr %B.addr.02, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 -; CHECK-NEXT: da analyze - none! +; CHECK-ALL-LABEL: 'strong9' +; CHECK-ALL-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: store i32 %conv, ptr %arrayidx, align 4 +; CHECK-ALL-NEXT: da analyze - none! +; CHECK-ALL-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: %0 = load i32, ptr %arrayidx2, align 4 +; CHECK-ALL-NEXT: da analyze - none! +; CHECK-ALL-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 +; CHECK-ALL-NEXT: da analyze - confused! +; CHECK-ALL-NEXT: Src: %0 = load i32, ptr %arrayidx2, align 4 --> Dst: %0 = load i32, ptr %arrayidx2, align 4 +; CHECK-ALL-NEXT: da analyze - none! +; CHECK-ALL-NEXT: Src: %0 = load i32, ptr %arrayidx2, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 +; CHECK-ALL-NEXT: da analyze - confused! +; CHECK-ALL-NEXT: Src: store i32 %0, ptr %B.addr.02, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 +; CHECK-ALL-NEXT: da analyze - none! +; +; CHECK-STRONG-SIV-LABEL: 'strong9' +; CHECK-STRONG-SIV-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: store i32 %conv, ptr %arrayidx, align 4 +; CHECK-STRONG-SIV-NEXT: da analyze - none! +; CHECK-STRONG-SIV-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: %0 = load i32, ptr %arrayidx2, align 4 +; CHECK-STRONG-SIV-NEXT: da analyze - flow [*|<]! +; CHECK-STRONG-SIV-NEXT: Src: store i32 %conv, ptr %arrayidx, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 +; CHECK-STRONG-SIV-NEXT: da analyze - confused! +; CHECK-STRONG-SIV-NEXT: Src: %0 = load i32, ptr %arrayidx2, align 4 --> Dst: %0 = load i32, ptr %arrayidx2, align 4 +; CHECK-STRONG-SIV-NEXT: da analyze - none! +; CHECK-STRONG-SIV-NEXT: Src: %0 = load i32, ptr %arrayidx2, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 +; CHECK-STRONG-SIV-NEXT: da analyze - confused! +; CHECK-STRONG-SIV-NEXT: Src: store i32 %0, ptr %B.addr.02, align 4 --> Dst: store i32 %0, ptr %B.addr.02, align 4 +; CHECK-STRONG-SIV-NEXT: da analyze - none! ; entry: %cmp1 = icmp eq i64 %n, 0 @@ -512,3 +528,45 @@ for.body: ; preds = %entry, %for.body for.end: ; preds = %for.body ret void } + + +;; for (long unsigned i = 0; i < 9223372036854775806; i++) +;; for (long unsigned j = 0; j < 2147483640; j++) +;; if (i < 3000000000) +;; A[i] = 0; +; +; FIXME: DependenceAnalysis fails to detect the dependency between A[i] and +; itself, while Strong SIV has been able to prove it. +define void @strong11(ptr %A) nounwind uwtable ssp { +; CHECK-ALL-LABEL: 'strong11' +; CHECK-ALL-NEXT: Src: store i32 0, ptr %arrayidx, align 4 --> Dst: store i32 0, ptr %arrayidx, align 4 +; CHECK-ALL-NEXT: da analyze - none! +; +; CHECK-STRONG-SIV-LABEL: 'strong11' +; CHECK-STRONG-SIV-NEXT: Src: store i32 0, ptr %arrayidx, align 4 --> Dst: store i32 0, ptr %arrayidx, align 4 +; CHECK-STRONG-SIV-NEXT: da analyze - consistent output [0 S]! +; +entry: + br label %for.cond1.preheader + +for.cond1.preheader: ; preds = %entry, %for.cond.cleanup3 + %i.017 = phi i64 [ 0, %entry ], [ %inc8, %for.cond.cleanup3 ] + %cmp5 = icmp samesign ult i64 %i.017, 3000000000 + %arrayidx = getelementptr inbounds nuw i32, ptr %A, i64 %i.017 + br i1 %cmp5, label %for.body4.us, label %for.cond.cleanup3 + +for.body4.us: ; preds = %for.cond1.preheader, %for.body4.us + %j.016.us = phi i64 [ %inc.us, %for.body4.us ], [ 0, %for.cond1.preheader ] + store i32 0, ptr %arrayidx, align 4 + %inc.us = add nuw nsw i64 %j.016.us, 1 + %exitcond.not = icmp eq i64 %inc.us, 2147483640 + br i1 %exitcond.not, label %for.cond.cleanup3, label %for.body4.us + +for.cond.cleanup: ; preds = %for.cond.cleanup3 + ret void + +for.cond.cleanup3: ; preds = %for.body4.us, %for.cond1.preheader + %inc8 = add nuw nsw i64 %i.017, 1 + %exitcond19.not = icmp eq i64 %inc8, 9223372036854775806 + br i1 %exitcond19.not, label %for.cond.cleanup, label %for.cond1.preheader +}