caio/clang-p2996
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Reland "[CodeGen] Fix unconditional branch duplication issue in bbsections"

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Reverted in 4c8d056f50 because it broke
buildbot `llvm-clang-x86_64-expensive-checks-debian` due to the AArch64
test generating invalid code. The issue still exists, but it's fixed in
D156767, so the AArch64 test should be added there.

Differential Revision: https://reviews.llvm.org/D158674
This commit is contained in:
Daniel Hoekwater
2023-08-21 16:29:02 +00:00
parent 6021c78fe5
commit c9f328844d
2 changed files with 26 additions and 1 deletions
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3
llvm/lib/CodeGen/BasicBlockSections.cpp
View File

@@ -258,7 +258,8 @@ void llvm::sortBasicBlocksAndUpdateBranches(
[[maybe_unused]] const MachineBasicBlock *EntryBlock = &MF.front();
SmallVector<MachineBasicBlock *> PreLayoutFallThroughs(MF.getNumBlockIDs());
for (auto &MBB : MF)
PreLayoutFallThroughs[MBB.getNumber()] = MBB.getFallThrough();
PreLayoutFallThroughs[MBB.getNumber()] =
MBB.getFallThrough(/*JumpToFallThrough=*/false);
MF.sort(MBBCmp);
assert(&MF.front() == EntryBlock &&

24
llvm/test/CodeGen/Generic/machine-function-splitter.ll
View File

@@ -6,6 +6,7 @@
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -split-machine-functions -mfs-psi-cutoff=0 -mfs-count-threshold=2000 | FileCheck %s --dump-input=always -check-prefixes=MFS-OPTS1,MFS-OPTS1-X86
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -split-machine-functions -mfs-psi-cutoff=950000 | FileCheck %s -check-prefixes=MFS-OPTS2,MFS-OPTS2-X86
; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu -split-machine-functions -mfs-split-ehcode | FileCheck %s -check-prefixes=MFS-EH-SPLIT,MFS-EH-SPLIT-X86
; RUN: llc < %s -mtriple=x86_64 -split-machine-functions -O0 -mfs-psi-cutoff=0 -mfs-count-threshold=10000 | FileCheck %s -check-prefixes=MFS-O0,MFS-O0-X86
; RUN: llc < %s -mtriple=aarch64-unknown-linux-gnu -enable-split-machine-functions -mfs-allow-unsupported-triple | FileCheck %s -check-prefixes=MFS-DEFAULTS,MFS-DEFAULTS-AARCH64
; RUN: llc < %s -mtriple=aarch64-unknown-linux-gnu -enable-split-machine-functions -mfs-allow-unsupported-triple -mfs-psi-cutoff=0 -mfs-count-threshold=2000 | FileCheck %s --dump-input=always -check-prefixes=MFS-OPTS1,MFS-OPTS1-AARCH64
@@ -462,6 +463,29 @@ define void @foo15(i1 zeroext %0, i1 zeroext %1) nounwind !prof !27 {
ret void
}
define void @foo16(i1 zeroext %0) nounwind !prof !14 !section_prefix !15 {
;; Check that an unconditional branch is only appended to a block
;; if it would fall through to the wrong block otherwise.
; MFS-O0-LABEL: foo16
; MFS-O0-X86: jmp
; MFS-O0-X86-NOT: jmp
; MFS-O0-AARCH64: br
; MFS-O0-AARCH64: br
; MFS-O0-AARCH64-NOT: br
; MFS-O0: .section .text.split.foo16
; MFS-O0-NEXT: foo16.cold
%2 = call i32 @baz()
br i1 false, label %3, label %5, !prof !25
3: ; preds = %1
%4 = call i32 @bar()
unreachable
5: ; preds = %1
%6 = tail call i32 @qux()
ret void
}
declare i32 @bar()
declare i32 @baz()
declare i32 @bam()