diff options
Diffstat (limited to 'build/build-clang/llvmorg-11-init-15486-gfc937806efd-dont-jump-to-landing-pads.patch')
| -rw-r--r-- | build/build-clang/llvmorg-11-init-15486-gfc937806efd-dont-jump-to-landing-pads.patch | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/build/build-clang/llvmorg-11-init-15486-gfc937806efd-dont-jump-to-landing-pads.patch b/build/build-clang/llvmorg-11-init-15486-gfc937806efd-dont-jump-to-landing-pads.patch new file mode 100644 index 0000000000..fee6798c59 --- /dev/null +++ b/build/build-clang/llvmorg-11-init-15486-gfc937806efd-dont-jump-to-landing-pads.patch @@ -0,0 +1,100 @@ +From d1c09fb47e2778538c5b1f918724d31d05497883 Mon Sep 17 00:00:00 2001 +From: Arthur Eubanks <aeubanks@google.com> +Date: Wed, 13 May 2020 16:33:09 -0700 +Subject: [PATCH] Don't jump to landing pads in Control Flow Optimizer + +Summary: Likely fixes https://bugs.llvm.org/show_bug.cgi?id=45858. + +Subscribers: hiraditya, llvm-commits + +Tags: #llvm + +Differential Revision: https://reviews.llvm.org/D80047 +--- + llvm/lib/CodeGen/BranchFolding.cpp | 18 ++++++------ + llvm/test/CodeGen/X86/branchfolding-ehpad.mir | 28 +++++++++++++++++++ + 2 files changed, 38 insertions(+), 8 deletions(-) + create mode 100644 llvm/test/CodeGen/X86/branchfolding-ehpad.mir + +diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp +index fb54b5d6c8d..4a822b58446 100644 +--- a/llvm/lib/CodeGen/BranchFolding.cpp ++++ b/llvm/lib/CodeGen/BranchFolding.cpp +@@ -991,10 +991,10 @@ bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB, + 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(); +@@ -1002,19 +1002,21 @@ bool BranchFolder::TryTailMergeBlocks(MachineBasicBlock *SuccBB, + // 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 +index 00000000000..d445cd20680 +--- /dev/null ++++ b/llvm/test/CodeGen/X86/branchfolding-ehpad.mir +@@ -0,0 +1,28 @@ ++# RUN: llc -mtriple=x86_64-windows-msvc -verify-machineinstrs -run-pass branch-folder -o - %s | FileCheck %s ++ ++# Check that branch-folder does not create a fallthrough to a landing pad. ++# Also make sure that the landing pad still can be tail merged. ++--- ++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): ++ ; CHECK-NOT: MOV8mi ++ bb.3(landing-pad): ++ MOV8mi $r13, 1, $noreg, 0, $noreg, 0 ++ JMP_1 %bb.5 ++ ; CHECK: bb.4: ++ bb.4: ++ MOV8mi $r13, 2, $noreg, 0, $noreg, 0 ++ bb.5: ++ RET 0 ++... +-- +2.24.1.windows.2 + |