Index: llvm/lib/Transforms/Utils/LoopUtils.cpp =================================================================== --- llvm/lib/Transforms/Utils/LoopUtils.cpp +++ llvm/lib/Transforms/Utils/LoopUtils.cpp @@ -729,8 +729,9 @@ // and outer loop so the other target doesn't need to an exit if (L->isLoopExiting(Latch)) { // TODO: Generalize ConstantFoldTerminator so that it can be used - // here without invalidating LCSSA. (Tricky case: header is an exit - // block of a preceeding sibling loop w/o dedicated exits.) + // here without invalidating LCSSA or MemorySSA. (Tricky case for + // LCSSA: header is an exit block of a preceeding sibling loop w/o + // dedicated exits.) const unsigned ExitIdx = L->contains(BI->getSuccessor(0)) ? 1 : 0; BasicBlock *ExitBB = BI->getSuccessor(ExitIdx); @@ -746,6 +747,8 @@ BI->eraseFromParent(); DTU.applyUpdates({{DominatorTree::Delete, Latch, Header}}); + if (MSSA) + MSSAU->applyUpdates({{DominatorTree::Delete, Latch, Header}}, DT); return; } } Index: llvm/test/Transforms/LoopDeletion/bbi-59728.ll =================================================================== --- /dev/null +++ llvm/test/Transforms/LoopDeletion/bbi-59728.ll @@ -0,0 +1,27 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt %s -verify-memoryssa -passes='loop-mssa(loop-deletion,loop-simplifycfg)' -S | FileCheck %s + +; This is a case where we failed to update memory SSA correctly in +; loop-deletion which escapes local verification, but causes a crash +; in loop-simplifycfg. +define void @func_45() { +; CHECK-LABEL: @func_45( +; CHECK-NEXT: entry: +; CHECK-NEXT: br label [[FOR_BODY45:%.*]] +; CHECK: for.body45: +; CHECK-NEXT: store i32 433429641, i32* undef, align 1 +; CHECK-NEXT: br label [[FOR_BODY45]] +; +entry: + br label %for.body45 + +for.body45: ; preds = %for.end72, %entry + br label %for.body48 + +for.body48: ; preds = %for.body48, %for.body45 + store i32 433429641, i32* undef, align 1 + br i1 undef, label %for.body48, label %for.end72 + +for.end72: ; preds = %for.body48 + br label %for.body45 +}