llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-llvm-analysis Author: None (llvmbot) <details> <summary>Changes</summary> Backport 07efe2c18a63423943a4f9d9daeada23601f84c8 Requested by: @<!-- -->nikic --- Full diff: https://github.com/llvm/llvm-project/pull/124895.diff 2 Files Affected: - (modified) llvm/lib/Analysis/ScalarEvolution.cpp (+12-14) - (modified) llvm/test/Analysis/ScalarEvolution/pr123550.ll (+4-4) ``````````diff diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 7d7d37b3d228dd..2ce40877b523e1 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -5917,20 +5917,18 @@ const SCEV *ScalarEvolution::createAddRecFromPHI(PHINode *PN) { // PHI(f(0), f({1,+,1})) --> f({0,+,1}) // Do not allow refinement in rewriting of BEValue. - if (isGuaranteedNotToCauseUB(BEValue)) { - const SCEV *Shifted = SCEVShiftRewriter::rewrite(BEValue, L, *this); - const SCEV *Start = SCEVInitRewriter::rewrite(Shifted, L, *this, false); - if (Shifted != getCouldNotCompute() && Start != getCouldNotCompute() && - ::impliesPoison(BEValue, Start)) { - const SCEV *StartVal = getSCEV(StartValueV); - if (Start == StartVal) { - // Okay, for the entire analysis of this edge we assumed the PHI - // to be symbolic. We now need to go back and purge all of the - // entries for the scalars that use the symbolic expression. - forgetMemoizedResults(SymbolicName); - insertValueToMap(PN, Shifted); - return Shifted; - } + const SCEV *Shifted = SCEVShiftRewriter::rewrite(BEValue, L, *this); + const SCEV *Start = SCEVInitRewriter::rewrite(Shifted, L, *this, false); + if (Shifted != getCouldNotCompute() && Start != getCouldNotCompute() && + isGuaranteedNotToCauseUB(Shifted) && ::impliesPoison(Shifted, Start)) { + const SCEV *StartVal = getSCEV(StartValueV); + if (Start == StartVal) { + // Okay, for the entire analysis of this edge we assumed the PHI + // to be symbolic. We now need to go back and purge all of the + // entries for the scalars that use the symbolic expression. + forgetMemoizedResults(SymbolicName); + insertValueToMap(PN, Shifted); + return Shifted; } } } diff --git a/llvm/test/Analysis/ScalarEvolution/pr123550.ll b/llvm/test/Analysis/ScalarEvolution/pr123550.ll index c1f2051248a12d..709da00935ef3a 100644 --- a/llvm/test/Analysis/ScalarEvolution/pr123550.ll +++ b/llvm/test/Analysis/ScalarEvolution/pr123550.ll @@ -1,16 +1,16 @@ ; NOTE: Assertions have been autogenerated by utils/update_analyze_test_checks.py UTC_ARGS: --version 5 ; RUN: opt -disable-output -passes='print<scalar-evolution>' < %s 2>&1 | FileCheck %s -; FIXME: This is a miscompile. +; %srem should have exit value 130. define i32 @test() { ; CHECK-LABEL: 'test' ; CHECK-NEXT: Classifying expressions for: @test ; CHECK-NEXT: %phi = phi i32 [ -173, %bb ], [ %sub, %loop ] -; CHECK-NEXT: --> (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw> U: empty-set S: empty-set Exits: -173 LoopDispositions: { %loop: Computable } +; CHECK-NEXT: --> %phi U: [-173,1) S: [-173,1) Exits: -173 LoopDispositions: { %loop: Variant } ; CHECK-NEXT: %iv2 = phi i32 [ 1, %bb ], [ %iv2.inc, %loop ] ; CHECK-NEXT: --> {1,+,1}<nuw><nsw><%loop> U: [1,2) S: [1,2) Exits: 1 LoopDispositions: { %loop: Computable } ; CHECK-NEXT: %srem = srem i32 729259140, %phi -; CHECK-NEXT: --> (729259140 + (-1 * (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw> * (729259140 /u (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw>)))<nuw><nsw> U: empty-set S: empty-set Exits: 729259140 LoopDispositions: { %loop: Computable } +; CHECK-NEXT: --> %srem U: [0,1073741824) S: [0,1073741824) Exits: 130 LoopDispositions: { %loop: Variant } ; CHECK-NEXT: %trunc = trunc i32 %iv2 to i8 ; CHECK-NEXT: --> {1,+,1}<%loop> U: [1,2) S: [1,2) Exits: 1 LoopDispositions: { %loop: Computable } ; CHECK-NEXT: %urem = urem i8 -83, %trunc @@ -22,7 +22,7 @@ define i32 @test() { ; CHECK-NEXT: %iv2.inc = add i32 %iv2, 1 ; CHECK-NEXT: --> {2,+,1}<nuw><nsw><%loop> U: [2,3) S: [2,3) Exits: 2 LoopDispositions: { %loop: Computable } ; CHECK-NEXT: %srem.lcssa = phi i32 [ %srem, %loop ] -; CHECK-NEXT: --> (729259140 + (-1 * (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw> * (729259140 /u (-173 + (-1 * (zext i8 ((-83 /u {0,+,1}<%loop>) * {0,+,-1}<%loop>) to i32))<nuw><nsw>)<nuw><nsw>)))<nuw><nsw> U: empty-set S: empty-set --> 729259140 U: [729259140,729259141) S: [729259140,729259141) +; CHECK-NEXT: --> %srem U: [0,1073741824) S: [0,1073741824) --> 130 U: [130,131) S: [130,131) ; CHECK-NEXT: Determining loop execution counts for: @test ; CHECK-NEXT: Loop %loop: backedge-taken count is i32 0 ; CHECK-NEXT: Loop %loop: constant max backedge-taken count is i32 0 `````````` </details> https://github.com/llvm/llvm-project/pull/124895 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
