shylie/llvm-project
1
0
Fork 0
Code Issues Pull Requests Actions 6 Packages Projects Releases Wiki Activity
llvm-project/llvm/test/Transforms/SimplifyCFG/unreachable-multi-basic-block-funclet.ll
Gábor Spaits 0a47e8c2fc
Reland [BasicBlockUtils] Handle funclets when detaching EH pad blocks (#159379) 
Fixes #148052 .

Last PR did not account for the scenario, when more than one instruction
used the `catchpad` label.
In that case I have deleted uses, which were already "choosen to be
iterated over" by the early increment iterator. This issue was not
visible in normal release build on x86, but luckily later on the address
sanitizer build it has found it on the buildbot.

Here is the diff from the last version of this PR: #158435
```diff
diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index 91e245e5e8f5..1dd8cb4ee584 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -106,7 +106,8 @@ void llvm::detachDeadBlocks(ArrayRef<BasicBlock *> BBs,
       // first block, the we would have possible cleanupret and catchret
       // instructions with poison arguments, which wouldn't be valid.
       if (isa<FuncletPadInst>(I)) {
-        for (User *User : make_early_inc_range(I.users())) {
+        SmallPtrSet<BasicBlock *, 4> UniqueEHRetBlocksToDelete;
+        for (User *User : I.users()) {
           Instruction *ReturnInstr = dyn_cast<Instruction>(User);
           // If we have a cleanupret or catchret block, replace it with just an
           // unreachable. The other alternative, that may use a catchpad is a
@@ -114,33 +115,12 @@ void llvm::detachDeadBlocks(ArrayRef<BasicBlock *> BBs,
           if (isa<CatchReturnInst>(ReturnInstr) ||
               isa<CleanupReturnInst>(ReturnInstr)) {
             BasicBlock *ReturnInstrBB = ReturnInstr->getParent();
-            // This catchret or catchpad basic block is detached now. Let the
-            // successors know it.
-            // This basic block also may have some predecessors too. For
-            // example the following LLVM-IR is valid:
-            //
-            //   [cleanuppad_block]
-            //            |
-            //    [regular_block]
-            //            |
-            //   [cleanupret_block]
-            //
-            // The IR after the cleanup will look like this:
-            //
-            //   [cleanuppad_block]
-            //            |
-            //    [regular_block]
-            //            |
-            //     [unreachable]
-            //
-            // So regular_block will lead to an unreachable block, which is also
-            // valid. There is no need to replace regular_block with unreachable
-            // in this context now.
-            // On the other hand, the cleanupret/catchret block's successors
-            // need to know about the deletion of their predecessors.
-            emptyAndDetachBlock(ReturnInstrBB, Updates, KeepOneInputPHIs);
+            UniqueEHRetBlocksToDelete.insert(ReturnInstrBB);
           }
         }
+        for (BasicBlock *EHRetBB :
+             make_early_inc_range(UniqueEHRetBlocksToDelete))
+          emptyAndDetachBlock(EHRetBB, Updates, KeepOneInputPHIs);
       }
     }
```
2025-09-19 17:00:17 -07:00

237 lines
6.1 KiB
LLVM
Raw Permalink Blame History

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
; RUN: opt -passes=simplifycfg -S < %s | FileCheck %s
; cleanuppad/cleanupret
define void @unreachable_cleanuppad_linear(i64 %shapes.1) personality ptr null {
; CHECK-LABEL: define void @unreachable_cleanuppad_linear(
; CHECK-SAME: i64 [[SHAPES_1:%.*]]) personality ptr null {
; CHECK-NEXT: [[START:.*:]]
; CHECK-NEXT: [[_7:%.*]] = icmp ult i64 0, [[SHAPES_1]]
; CHECK-NEXT: ret void
;
start:
%_7 = icmp ult i64 0, %shapes.1
ret void
funclet:
%cleanuppad = cleanuppad within none []
br label %funclet_end
funclet_end:
cleanupret from %cleanuppad unwind to caller
}
define void @unreachable_cleanuppad_linear_middle_block(i64 %shapes.1) personality ptr null {
; CHECK-LABEL: define void @unreachable_cleanuppad_linear_middle_block(
; CHECK-SAME: i64 [[SHAPES_1:%.*]]) personality ptr null {
; CHECK-NEXT: [[START:.*:]]
; CHECK-NEXT: [[_7:%.*]] = icmp ult i64 0, [[SHAPES_1]]
; CHECK-NEXT: ret void
;
start:
%_7 = icmp ult i64 0, %shapes.1
ret void
funclet:
%cleanuppad = cleanuppad within none []
br label %middle_block
middle_block:
%tmp1 = add i64 %shapes.1, 42
br label %funclet_end
funclet_end:
cleanupret from %cleanuppad unwind to caller
}
define void @unreachable_cleanuppad_multiple_predecessors(i64 %shapes.1) personality ptr null {
; CHECK-LABEL: define void @unreachable_cleanuppad_multiple_predecessors(
; CHECK-SAME: i64 [[SHAPES_1:%.*]]) personality ptr null {
; CHECK-NEXT: [[START:.*:]]
; CHECK-NEXT: [[_7:%.*]] = icmp ult i64 0, [[SHAPES_1]]
; CHECK-NEXT: ret void
;
start:
%_7 = icmp ult i64 0, %shapes.1
ret void
funclet:
%cleanuppad = cleanuppad within none []
switch i64 %shapes.1, label %otherwise [ i64 0, label %one
i64 1, label %two
i64 42, label %three ]
one:
br label %funclet_end
two:
br label %funclet_end
three:
br label %funclet_end
otherwise:
br label %funclet_end
funclet_end:
cleanupret from %cleanuppad unwind to caller
}
; catchpad/catchret
define void @unreachable_catchpad_linear(i64 %shapes.1) personality ptr null {
; CHECK-LABEL: define void @unreachable_catchpad_linear(
; CHECK-SAME: i64 [[SHAPES_1:%.*]]) personality ptr null {
; CHECK-NEXT: [[START:.*:]]
; CHECK-NEXT: [[_7:%.*]] = icmp ult i64 0, [[SHAPES_1]]
; CHECK-NEXT: ret void
;
start:
%_7 = icmp ult i64 0, %shapes.1
ret void
dispatch:
%cs = catchswitch within none [label %funclet] unwind to caller
funclet:
%cleanuppad = catchpad within %cs []
br label %funclet_end
funclet_end:
catchret from %cleanuppad to label %unreachable
unreachable:
unreachable
}
define void @unreachable_catchpad_multiple_predecessors(i64 %shapes.1) personality ptr null {
; CHECK-LABEL: define void @unreachable_catchpad_multiple_predecessors(
; CHECK-SAME: i64 [[SHAPES_1:%.*]]) personality ptr null {
; CHECK-NEXT: [[START:.*:]]
; CHECK-NEXT: [[_7:%.*]] = icmp ult i64 0, [[SHAPES_1]]
; CHECK-NEXT: ret void
;
start:
%_7 = icmp ult i64 0, %shapes.1
ret void
dispatch:
%cs = catchswitch within none [label %funclet] unwind to caller
funclet:
%cleanuppad = catchpad within %cs []
switch i64 %shapes.1, label %otherwise [ i64 0, label %one
i64 1, label %two
i64 42, label %three ]
one:
br label %funclet_end
two:
br label %funclet_end
three:
br label %funclet_end
otherwise:
br label %funclet_end
funclet_end:
catchret from %cleanuppad to label %unreachable
unreachable:
unreachable
}
; Issue reproducer
define void @gh148052(i64 %shapes.1) personality ptr null {
; CHECK-LABEL: define void @gh148052(
; CHECK-SAME: i64 [[SHAPES_1:%.*]]) personality ptr null {
; CHECK-NEXT: [[START:.*:]]
; CHECK-NEXT: [[_7:%.*]] = icmp ult i64 0, [[SHAPES_1]]
; CHECK-NEXT: call void @llvm.assume(i1 [[_7]])
; CHECK-NEXT: ret void
;
start:
%_7 = icmp ult i64 0, %shapes.1
br i1 %_7, label %bb1, label %panic
bb1:
%_11 = icmp ult i64 0, %shapes.1
br i1 %_11, label %bb3, label %panic1
panic:
unreachable
bb3:
ret void
panic1:
invoke void @func(i64 0, i64 0, ptr null)
to label %unreachable unwind label %funclet_bb14
funclet_bb14:
%cleanuppad = cleanuppad within none []
br label %bb13
unreachable:
unreachable
bb10:
cleanupret from %cleanuppad5 unwind to caller
funclet_bb10:
%cleanuppad5 = cleanuppad within none []
br label %bb10
bb13:
cleanupret from %cleanuppad unwind label %funclet_bb10
}
%struct.foo = type { ptr, %struct.eggs, ptr }
%struct.eggs = type { ptr, ptr, ptr }
declare x86_thiscallcc ptr @quux(ptr, ptr, i32)
define x86_thiscallcc ptr @baz(ptr %arg, ptr %arg1, ptr %arg2, i1 %arg3, ptr %arg4) personality ptr null {
; CHECK-LABEL: define x86_thiscallcc ptr @baz(
; CHECK-SAME: ptr [[ARG:%.*]], ptr [[ARG1:%.*]], ptr [[ARG2:%.*]], i1 [[ARG3:%.*]], ptr [[ARG4:%.*]]) personality ptr null {
; CHECK-NEXT: [[BB:.*:]]
; CHECK-NEXT: [[ALLOCA:%.*]] = alloca [2 x %struct.foo], align 4
; CHECK-NEXT: [[INVOKE:%.*]] = call x86_thiscallcc ptr @quux(ptr null, ptr null, i32 0) #[[ATTR1:[0-9]+]]
; CHECK-NEXT: unreachable
;
bb:
%alloca = alloca [2 x %struct.foo], align 4
%invoke = invoke x86_thiscallcc ptr @quux(ptr null, ptr null, i32 0)
to label %bb5 unwind label %bb10
bb5: ; preds = %bb
%getelementptr = getelementptr i8, ptr %arg, i32 20
%call = call x86_thiscallcc ptr null(ptr null, ptr null, i32 0)
br label %bb6
bb6: ; preds = %bb10, %bb5
%phi = phi ptr [ null, %bb10 ], [ null, %bb5 ]
ret ptr %phi
bb7: ; No predecessors!
%cleanuppad = cleanuppad within none []
%getelementptr8 = getelementptr i8, ptr %arg2, i32 -20
%icmp = icmp eq ptr %arg, null
br label %bb9
bb9: ; preds = %bb7
cleanupret from %cleanuppad unwind label %bb10
bb10: ; preds = %bb9, %bb
%phi11 = phi ptr [ %arg, %bb9 ], [ null, %bb ]
%cleanuppad12 = cleanuppad within none []
%getelementptr13 = getelementptr i8, ptr %phi11, i32 -20
store i32 0, ptr %phi11, align 4
br label %bb6
}
declare void @func(i64, i64, ptr)
Reference in New Issue View Git Blame Copy Permalink