diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp --- a/llvm/lib/CodeGen/BranchFolding.cpp +++ b/llvm/lib/CodeGen/BranchFolding.cpp @@ -921,10 +921,10 @@ continue; } - // If one of the blocks is the entire common tail (and not the entry - // block, which we can't jump to), we can treat all blocks with this same - // tail at once. Use PredBB if that is one of the possibilities, as that - // will not introduce any extra branches. + // If one of the blocks is the entire common tail (and is not the entry + // block/an EH pad, which we can't jump to), we can treat all blocks with + // this same tail at once. Use PredBB if that is one of the possibilities, + // as that will not introduce any extra branches. MachineBasicBlock *EntryBB = &MergePotentials.front().getBlock()->getParent()->front(); unsigned commonTailIndex = SameTails.size(); @@ -932,19 +932,21 @@ // into the other. if (SameTails.size() == 2 && SameTails[0].getBlock()->isLayoutSuccessor(SameTails[1].getBlock()) && - SameTails[1].tailIsWholeBlock()) + SameTails[1].tailIsWholeBlock() && !SameTails[1].getBlock()->isEHPad()) commonTailIndex = 1; else if (SameTails.size() == 2 && SameTails[1].getBlock()->isLayoutSuccessor( - SameTails[0].getBlock()) && - SameTails[0].tailIsWholeBlock()) + SameTails[0].getBlock()) && + SameTails[0].tailIsWholeBlock() && + !SameTails[0].getBlock()->isEHPad()) commonTailIndex = 0; else { // Otherwise just pick one, favoring the fall-through predecessor if // there is one. for (unsigned i = 0, e = SameTails.size(); i != e; ++i) { MachineBasicBlock *MBB = SameTails[i].getBlock(); - if (MBB == EntryBB && SameTails[i].tailIsWholeBlock()) + if ((MBB == EntryBB || MBB->isEHPad()) && + SameTails[i].tailIsWholeBlock()) continue; if (MBB == PredBB) { commonTailIndex = i; diff --git a/llvm/test/CodeGen/X86/branchfolding-ehpad.mir b/llvm/test/CodeGen/X86/branchfolding-ehpad.mir new file mode 100644 --- /dev/null +++ b/llvm/test/CodeGen/X86/branchfolding-ehpad.mir @@ -0,0 +1,23 @@ +# RUN: llc -mtriple=x86_64-windows-msvc -verify-machineinstrs -run-pass branch-folder -o - %s | FileCheck %s +--- +name: foo +body: | + ; CHECK-LABEL: name: foo + bb.0: + successors: %bb.1, %bb.3 + bb.1: + JCC_1 %bb.4, 5, implicit killed $eflags + bb.2: + MOV8mi $r13, 1, $noreg, 0, $noreg, 0 + JMP_1 %bb.5 + ; CHECK: bb.2: + ; CHECK-NOT: successors: {{.*}}bb.3 + ; CHECK: bb.3 (landing-pad): + bb.3(landing-pad): + MOV8mi $r13, 1, $noreg, 0, $noreg, 0 + JMP_1 %bb.5 + bb.4: + MOV8mi $r13, 2, $noreg, 0, $noreg, 0 + bb.5: + RET 0 +...