llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT--> @llvm/pr-subscribers-llvm-transforms @llvm/pr-subscribers-llvm-analysis Author: None (llvmbot) <details> <summary>Changes</summary> Backport ae08969a2068dd327fbf4d0f606550574fbb9e45 7aed53eb1982113e825534f0f66d0a0e46e7a5ed Requested by: @<!-- -->nikic --- Full diff: https://github.com/llvm/llvm-project/pull/126492.diff 2 Files Affected: - (modified) llvm/lib/Analysis/ScalarEvolution.cpp (+6) - (added) llvm/test/Transforms/IndVarSimplify/pr126012.ll (+53) ``````````diff diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp index 2ce40877b523e10..c71202c8dd58e4d 100644 --- a/llvm/lib/Analysis/ScalarEvolution.cpp +++ b/llvm/lib/Analysis/ScalarEvolution.cpp @@ -12402,6 +12402,12 @@ bool ScalarEvolution::isImpliedViaMerge(CmpPredicate Pred, const SCEV *LHS, // iteration of a loop. if (!properlyDominates(L, LBB)) return false; + // Addrecs are considered to properly dominate their loop, so are missed + // by the previous check. Discard any values that have computable + // evolution in this loop. + if (auto *Loop = LI.getLoopFor(LBB)) + if (hasComputableLoopEvolution(L, Loop)) + return false; if (!ProvedEasily(L, RHS)) return false; } diff --git a/llvm/test/Transforms/IndVarSimplify/pr126012.ll b/llvm/test/Transforms/IndVarSimplify/pr126012.ll new file mode 100644 index 000000000000000..5189fe020dd3bfd --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/pr126012.ll @@ -0,0 +1,53 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5 +; RUN: opt -S -passes=indvars < %s | FileCheck %s + +; Do not infer that %cmp is true. The %indvar3 input of %indvar2 comes from +; a previous iteration, so we should not compare it to a value from the current +; iteration. +define i32 @test() { +; CHECK-LABEL: define i32 @test() { +; CHECK-NEXT: [[ENTRY:.*]]: +; CHECK-NEXT: br label %[[FOR_PREHEADER:.*]] +; CHECK: [[FOR_PREHEADER]]: +; CHECK-NEXT: [[INDVAR1:%.*]] = phi i32 [ 0, %[[ENTRY]] ], [ [[PHI:%.*]], %[[FOR_INC:.*]] ] +; CHECK-NEXT: [[INDVAR2:%.*]] = phi i32 [ 1, %[[ENTRY]] ], [ [[INDVAR3:%.*]], %[[FOR_INC]] ] +; CHECK-NEXT: [[INDVAR3]] = phi i32 [ 0, %[[ENTRY]] ], [ [[INC:%.*]], %[[FOR_INC]] ] +; CHECK-NEXT: [[COND1:%.*]] = icmp eq i32 [[INDVAR3]], 0 +; CHECK-NEXT: br i1 [[COND1]], label %[[FOR_INC]], label %[[FOR_END:.*]] +; CHECK: [[FOR_END]]: +; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i32 [[INDVAR2]], 0 +; CHECK-NEXT: [[EXT:%.*]] = zext i1 [[CMP]] to i32 +; CHECK-NEXT: br label %[[FOR_INC]] +; CHECK: [[FOR_INC]]: +; CHECK-NEXT: [[PHI]] = phi i32 [ [[EXT]], %[[FOR_END]] ], [ 0, %[[FOR_PREHEADER]] ] +; CHECK-NEXT: [[INC]] = add nuw nsw i32 [[INDVAR3]], 1 +; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i32 [[INDVAR3]], 2 +; CHECK-NEXT: br i1 [[EXITCOND]], label %[[FOR_EXIT:.*]], label %[[FOR_PREHEADER]] +; CHECK: [[FOR_EXIT]]: +; CHECK-NEXT: [[INDVAR1_LCSSA:%.*]] = phi i32 [ [[INDVAR1]], %[[FOR_INC]] ] +; CHECK-NEXT: ret i32 [[INDVAR1_LCSSA]] +; +entry: + br label %for.preheader + +for.preheader: + %indvar1 = phi i32 [ 0, %entry ], [ %phi, %for.inc ] + %indvar2 = phi i32 [ 1, %entry ], [ %indvar3, %for.inc ] + %indvar3 = phi i32 [ 0, %entry ], [ %inc, %for.inc ] + %cond1 = icmp eq i32 %indvar3, 0 + br i1 %cond1, label %for.inc, label %for.end + +for.end: + %cmp = icmp sgt i32 %indvar2, 0 + %ext = zext i1 %cmp to i32 + br label %for.inc + +for.inc: + %phi = phi i32 [ %ext, %for.end ], [ 0, %for.preheader ] + %inc = add i32 %indvar3, 1 + %exitcond = icmp eq i32 %indvar3, 2 + br i1 %exitcond, label %for.exit, label %for.preheader + +for.exit: + ret i32 %indvar1 +} `````````` </details> https://github.com/llvm/llvm-project/pull/126492 _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
