[llvm] f892cc3 - [BranchFolding] Fix missing predecessors of landing-pad (#77608)
via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 11 06:09:46 PST 2024
Author: HaohaiWen
Date: 2024-01-11T22:09:41+08:00
New Revision: f892cc36fda6d25d4f7cbf68e95b17ba0af040b8
URL: https://github.com/llvm/llvm-project/commit/f892cc36fda6d25d4f7cbf68e95b17ba0af040b8
DIFF: https://github.com/llvm/llvm-project/commit/f892cc36fda6d25d4f7cbf68e95b17ba0af040b8.diff
LOG: [BranchFolding] Fix missing predecessors of landing-pad (#77608)
When removing an empty machine basic block, all of its successors should
be inherited by its fall through MBB. This keeps CFG as only have one
entry which is required by LiveDebugValues.
Reland #77441 as LiveDebugValues test.
Added:
llvm/test/CodeGen/X86/windows-seh-EHa-PreserveCFG.ll
Modified:
llvm/lib/CodeGen/BranchFolding.cpp
llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir
Removed:
################################################################################
diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index 0801296cab49f8..599b7c72b2f5c6 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -1363,6 +1363,14 @@ bool BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) {
MachineBasicBlock *Pred = *(MBB->pred_end()-1);
Pred->ReplaceUsesOfBlockWith(MBB, &*FallThrough);
}
+ // Add rest successors of MBB to successors of FallThrough. Those
+ // successors are not directly reachable via MBB, so it should be
+ // landing-pad.
+ for (auto SI = MBB->succ_begin(), SE = MBB->succ_end(); SI != SE; ++SI)
+ if (*SI != &*FallThrough && !FallThrough->isSuccessor(*SI)) {
+ assert((*SI)->isEHPad() && "Bad CFG");
+ FallThrough->copySuccessor(MBB, SI);
+ }
// If MBB was the target of a jump table, update jump tables to go to the
// fallthrough instead.
if (MachineJumpTableInfo *MJTI = MF.getJumpTableInfo())
@@ -1624,6 +1632,15 @@ bool BranchFolder::OptimizeBlock(MachineBasicBlock *MBB) {
} else {
DidChange = true;
PMBB->ReplaceUsesOfBlockWith(MBB, CurTBB);
+ // Add rest successors of MBB to successors of CurTBB. Those
+ // successors are not directly reachable via MBB, so it should be
+ // landing-pad.
+ for (auto SI = MBB->succ_begin(), SE = MBB->succ_end(); SI != SE;
+ ++SI)
+ if (*SI != CurTBB && !CurTBB->isSuccessor(*SI)) {
+ assert((*SI)->isEHPad() && "Bad CFG");
+ CurTBB->copySuccessor(MBB, SI);
+ }
// If this change resulted in PMBB ending in a conditional
// branch where both conditions go to the same destination,
// change this to an unconditional branch.
diff --git a/llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir b/llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir
index a494701c2a3997..8eef5450e252a6 100644
--- a/llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir
+++ b/llvm/test/CodeGen/X86/branchfolding-landingpad-cfg.mir
@@ -9,6 +9,8 @@ body: |
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.1:
+ ; CHECK-NEXT: successors: %bb.2(0x00000800)
+ ; CHECK-NEXT: {{ $}}
; CHECK-NEXT: RET 0
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: bb.2 (machine-block-address-taken, landing-pad, ehfunclet-entry):
diff --git a/llvm/test/CodeGen/X86/windows-seh-EHa-PreserveCFG.ll b/llvm/test/CodeGen/X86/windows-seh-EHa-PreserveCFG.ll
new file mode 100644
index 00000000000000..38461dcbe53f34
--- /dev/null
+++ b/llvm/test/CodeGen/X86/windows-seh-EHa-PreserveCFG.ll
@@ -0,0 +1,80 @@
+; RUN: llc -mtriple=x86_64-pc-windows-msvc %s
+define dso_local void @main(ptr %addr, ptr %src, ptr %dst) personality ptr @__CxxFrameHandler3 !dbg !11 {
+entry:
+ %tmp0 = load float, ptr %src
+ %src1 = getelementptr inbounds float, ptr %src, i64 1
+ %tmp1 = load float, ptr %src1
+ %src2 = getelementptr inbounds float, ptr %src, i64 2
+ %tmp2 = load float, ptr %src2
+ %src3 = getelementptr inbounds float, ptr %src, i64 3
+ %tmp3 = load float, ptr %src3
+ %src4 = getelementptr inbounds float, ptr %src, i64 4
+ %tmp4 = load float, ptr %src4
+ %src5 = getelementptr inbounds float, ptr %src, i64 5
+ %tmp5 = load float, ptr %src5
+ %src6 = getelementptr inbounds float, ptr %src, i64 6
+ %tmp6 = load float, ptr %src6
+ invoke void @foo(ptr %addr)
+ to label %scope_begin unwind label %ehcleanup1, !dbg !13
+
+scope_begin:
+ invoke void @llvm.seh.scope.begin()
+ to label %scope_end unwind label %ehcleanup, !dbg !13
+
+scope_end:
+ invoke void @llvm.seh.scope.end()
+ to label %finish unwind label %ehcleanup, !dbg !13
+
+ehcleanup:
+ %0 = cleanuppad within none [], !dbg !13
+ call void @llvm.dbg.value(metadata ptr %addr, metadata !12, metadata !DIExpression()), !dbg !13
+ call void @foo(ptr %addr) [ "funclet"(token %0) ], !dbg !13
+ cleanupret from %0 unwind label %ehcleanup1, !dbg !13
+
+ehcleanup1:
+ %1 = cleanuppad within none [], !dbg !13
+ call void @foo(ptr %addr) [ "funclet"(token %1) ], !dbg !13
+ cleanupret from %1 unwind to caller, !dbg !13
+
+finish:
+ store float %tmp0, ptr %dst
+ %dst1 = getelementptr inbounds float, ptr %dst, i64 1
+ store float %tmp1, ptr %dst1
+ %dst2 = getelementptr inbounds float, ptr %dst, i64 2
+ store float %tmp2, ptr %dst2
+ %dst3 = getelementptr inbounds float, ptr %dst, i64 3
+ store float %tmp3, ptr %dst3
+ %dst4 = getelementptr inbounds float, ptr %dst, i64 4
+ store float %tmp4, ptr %dst4
+ %dst5 = getelementptr inbounds float, ptr %dst, i64 5
+ store float %tmp5, ptr %dst5
+ %dst6 = getelementptr inbounds float, ptr %dst, i64 6
+ store float %tmp6, ptr %dst6
+ ret void
+}
+
+declare dso_local void @llvm.seh.scope.begin()
+declare dso_local void @llvm.seh.scope.end()
+declare dso_local i32 @__CxxFrameHandler3(...)
+declare dso_local void @foo(ptr %addr)
+declare void @llvm.dbg.value(metadata, metadata, metadata)
+
+!llvm.module.flags = !{!0, !1, !2, !3}
+!llvm.dbg.cu = !{!14}
+
+!0 = !{i32 2, !"eh-asynch", i32 1}
+!1 = !{i32 2, !"CodeView", i32 1}
+!2 = !{i32 2, !"Debug Info Version", i32 3}
+!3 = !{i32 7, !"uwtable", i32 2}
+
+!4 = !DIBasicType(name: "float", size: 32, encoding: DW_ATE_float)
+!5 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !4, size: 64)
+!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!7 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !6, size: 64)
+!8 = !DISubroutineType(types: !9)
+!9 = !{null, !7, !5, !5}
+!10 = !DIFile(filename: "c:/main.cpp", directory: "")
+!11 = distinct !DISubprogram(name: "main", scope: !10, file: !10, line: 5, type: !8, scopeLine: 11, unit: !14)
+!12 = !DILocalVariable(name: "addr", scope: !11, file: !10, line: 5, type: !7)
+!13 = !DILocation(line: 7, scope: !11)
+!14 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !10, isOptimized: true, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
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