[llvm] 3c5b1f2 - [SimplifyCFG] When eliminating `unreachable` landing pads, mark `call`s as `nounwind`
Roman Lebedev via llvm-commits
llvm-commits at lists.llvm.org
Thu Jan 12 13:42:29 PST 2023
Author: Roman Lebedev
Date: 2023-01-13T00:41:58+03:00
New Revision: 3c5b1f2d94d021005ce3769a4402d4a4ae843989
URL: https://github.com/llvm/llvm-project/commit/3c5b1f2d94d021005ce3769a4402d4a4ae843989
DIFF: https://github.com/llvm/llvm-project/commit/3c5b1f2d94d021005ce3769a4402d4a4ae843989.diff
LOG: [SimplifyCFG] When eliminating `unreachable` landing pads, mark `call`s as `nounwind`
We really can't recover that knowledge, and `nounwind` knowledge,
(and not just a lack of the unwind edge, aka `call` instead of `invoke`),
is e.g. part of the reasoning in e.g. `mayHaveSideEffects()`.
Note that this is call-site-specific knowledge,
just because some callsite had an `unreachable`
unwind edge, does not mean that all will.
Added:
Modified:
llvm/include/llvm/Transforms/Utils/Local.h
llvm/lib/Transforms/Utils/Local.cpp
llvm/lib/Transforms/Utils/SimplifyCFG.cpp
llvm/test/Transforms/SimplifyCFG/2011-09-05-TrivialLPad.ll
llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
llvm/test/Transforms/SimplifyCFG/X86/2010-03-30-InvokeCrash.ll
llvm/test/Transforms/SimplifyCFG/X86/bug-25299.ll
llvm/test/Transforms/SimplifyCFG/X86/empty-cleanuppad.ll
llvm/test/Transforms/SimplifyCFG/empty-catchpad.ll
llvm/test/Transforms/SimplifyCFG/invoke_unwind.ll
llvm/test/Transforms/SimplifyCFG/invoke_unwind_lifetime.ll
llvm/test/Transforms/SimplifyCFG/lifetime-landingpad.ll
llvm/test/Transforms/SimplifyCFG/wineh-unreachable.ll
Removed:
################################################################################
diff --git a/llvm/include/llvm/Transforms/Utils/Local.h b/llvm/include/llvm/Transforms/Utils/Local.h
index 1ad1e7b948c16..d59c5e0033f5f 100644
--- a/llvm/include/llvm/Transforms/Utils/Local.h
+++ b/llvm/include/llvm/Transforms/Utils/Local.h
@@ -360,7 +360,12 @@ BasicBlock *changeToInvokeAndSplitBasicBlock(CallInst *CI,
///
/// \param BB Block whose terminator will be replaced. Its terminator must
/// have an unwind successor.
-void removeUnwindEdge(BasicBlock *BB, DomTreeUpdater *DTU = nullptr);
+/// \param WouldUnwindBeUB What is the behaviour should the call actually
+/// unwind? For example, if the original landing pad
+/// unconditionally ended with `unreachable`,
+/// then the unwind would be UB.
+void removeUnwindEdge(BasicBlock *BB, bool WouldUnwindBeUB = false,
+ DomTreeUpdater *DTU = nullptr);
/// Remove all blocks that can not be reached from the function's entry.
///
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index d5d0232d7c1e8..569eee3a39d6c 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -2557,11 +2557,14 @@ static bool markAliveBlocks(Function &F,
return Changed;
}
-void llvm::removeUnwindEdge(BasicBlock *BB, DomTreeUpdater *DTU) {
+void llvm::removeUnwindEdge(BasicBlock *BB, bool WouldUnwindBeUB,
+ DomTreeUpdater *DTU) {
Instruction *TI = BB->getTerminator();
if (auto *II = dyn_cast<InvokeInst>(TI)) {
- changeToCall(II, DTU);
+ CallInst *CI = changeToCall(II, DTU);
+ if (WouldUnwindBeUB && !CI->doesNotThrow())
+ CI->setDoesNotThrow();
return;
}
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 870dc2b16a092..1ce412a4f5dca 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -5184,7 +5184,7 @@ bool SimplifyCFGOpt::simplifyUnreachable(UnreachableInst *UI) {
DTU->applyUpdates(Updates);
Updates.clear();
}
- removeUnwindEdge(TI->getParent(), DTU);
+ removeUnwindEdge(TI->getParent(), /*WouldUnwindBeUB=*/true, DTU);
Changed = true;
}
} else if (auto *CSI = dyn_cast<CatchSwitchInst>(TI)) {
diff --git a/llvm/test/Transforms/SimplifyCFG/2011-09-05-TrivialLPad.ll b/llvm/test/Transforms/SimplifyCFG/2011-09-05-TrivialLPad.ll
index d7368efa1eae6..bc5118cb39e83 100644
--- a/llvm/test/Transforms/SimplifyCFG/2011-09-05-TrivialLPad.ll
+++ b/llvm/test/Transforms/SimplifyCFG/2011-09-05-TrivialLPad.ll
@@ -7,7 +7,7 @@ declare void @bar()
define i32 @foo() personality ptr @__gxx_personality_v0 {
; CHECK-LABEL: @foo(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @bar()
+; CHECK-NEXT: call void @bar() #[[ATTR0:[0-9]+]]
; CHECK-NEXT: ret i32 0
;
entry:
@@ -24,3 +24,6 @@ lpad:
}
declare i32 @__gxx_personality_v0(i32, i64, ptr, ptr)
+;.
+; CHECK: attributes #[[ATTR0]] = { nounwind }
+;.
diff --git a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
index 94d1fa54159d7..7fe32dfc244d7 100644
--- a/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
+++ b/llvm/test/Transforms/SimplifyCFG/UnreachableEliminate.ll
@@ -20,7 +20,7 @@ F:
define void @test2() personality ptr @__gxx_personality_v0 {
; CHECK-LABEL: @test2(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @test2()
+; CHECK-NEXT: call void @test2() #[[ATTR3:[0-9]+]]
; CHECK-NEXT: ret void
;
entry:
@@ -570,4 +570,5 @@ attributes #0 = { null_pointer_is_valid }
; CHECK: attributes #[[ATTR0:[0-9]+]] = { nocallback nofree nosync nounwind willreturn memory(inaccessiblemem: readwrite) }
; CHECK: attributes #[[ATTR1:[0-9]+]] = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }
; CHECK: attributes #[[ATTR2:[0-9]+]] = { null_pointer_is_valid }
+; CHECK: attributes #[[ATTR3]] = { nounwind }
;.
diff --git a/llvm/test/Transforms/SimplifyCFG/X86/2010-03-30-InvokeCrash.ll b/llvm/test/Transforms/SimplifyCFG/X86/2010-03-30-InvokeCrash.ll
index dacd2ddc506a9..321df6211f71e 100644
--- a/llvm/test/Transforms/SimplifyCFG/X86/2010-03-30-InvokeCrash.ll
+++ b/llvm/test/Transforms/SimplifyCFG/X86/2010-03-30-InvokeCrash.ll
@@ -9,7 +9,7 @@ declare void @bar(i32)
define void @foo() personality ptr @__gxx_personality_v0 {
; CHECK-LABEL: @foo(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @bar(i32 undef)
+; CHECK-NEXT: call void @bar(i32 undef) #[[ATTR0:[0-9]+]]
; CHECK-NEXT: ret void
;
entry:
@@ -26,3 +26,6 @@ u: ; preds = %entry
}
declare i32 @__gxx_personality_v0(...)
+;.
+; CHECK: attributes #[[ATTR0]] = { nounwind }
+;.
diff --git a/llvm/test/Transforms/SimplifyCFG/X86/bug-25299.ll b/llvm/test/Transforms/SimplifyCFG/X86/bug-25299.ll
index da5c976873d72..6cbc1cbf7465c 100644
--- a/llvm/test/Transforms/SimplifyCFG/X86/bug-25299.ll
+++ b/llvm/test/Transforms/SimplifyCFG/X86/bug-25299.ll
@@ -9,10 +9,10 @@ target triple = "x86_64-unknown-linux-gnu"
define void @f(i1 %B) personality i1 undef {
; CHECK-LABEL: @f(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @g()
+; CHECK-NEXT: call void @g() #[[ATTR0:[0-9]+]]
; CHECK-NEXT: br label [[CONTINUE:%.*]]
; CHECK: continue:
-; CHECK-NEXT: call void @g()
+; CHECK-NEXT: call void @g() #[[ATTR0]]
; CHECK-NEXT: br label [[CONTINUE]]
;
entry:
@@ -42,3 +42,6 @@ cleanup2: ; preds = %continue
}
declare void @g()
+;.
+; CHECK: attributes #[[ATTR0]] = { nounwind }
+;.
diff --git a/llvm/test/Transforms/SimplifyCFG/X86/empty-cleanuppad.ll b/llvm/test/Transforms/SimplifyCFG/X86/empty-cleanuppad.ll
index 7e86b342ede22..e6fdcba655b21 100644
--- a/llvm/test/Transforms/SimplifyCFG/X86/empty-cleanuppad.ll
+++ b/llvm/test/Transforms/SimplifyCFG/X86/empty-cleanuppad.ll
@@ -20,7 +20,7 @@ target triple = "x86_64-pc-windows-msvc18.0.0"
define void @f1() personality ptr @__CxxFrameHandler3 {
; CHECK-LABEL: @f1(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @g()
+; CHECK-NEXT: call void @g() #[[ATTR1:[0-9]+]]
; CHECK-NEXT: ret void
;
entry:
@@ -189,7 +189,7 @@ ehcleanup.1:
define void @f4() personality ptr @__CxxFrameHandler3 {
; CHECK-LABEL: @f4(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @g()
+; CHECK-NEXT: call void @g() #[[ATTR1]]
; CHECK-NEXT: invoke void @g()
; CHECK-NEXT: to label [[TRY_CONT:%.*]] unwind label [[CATCH_DISPATCH:%.*]]
; CHECK: catch.dispatch:
@@ -473,7 +473,7 @@ try.cont:
define void @f10(i32 %V) personality ptr @__CxxFrameHandler3 {
; CHECK-LABEL: @f10(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @g()
+; CHECK-NEXT: call void @g() #[[ATTR1]]
; CHECK-NEXT: unreachable
;
entry:
@@ -559,4 +559,5 @@ declare void @llvm.lifetime.start.p0(i64, ptr nocapture)
declare void @llvm.lifetime.end.p0(i64, ptr nocapture)
;.
; CHECK: attributes #[[ATTR0:[0-9]+]] = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+; CHECK: attributes #[[ATTR1]] = { nounwind }
;.
diff --git a/llvm/test/Transforms/SimplifyCFG/empty-catchpad.ll b/llvm/test/Transforms/SimplifyCFG/empty-catchpad.ll
index 767817bf1c5d7..e86425b9f25b0 100644
--- a/llvm/test/Transforms/SimplifyCFG/empty-catchpad.ll
+++ b/llvm/test/Transforms/SimplifyCFG/empty-catchpad.ll
@@ -40,7 +40,7 @@ exit:
define void @test2() personality ptr @ProcessCLRException {
; CHECK-LABEL: @test2(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @f()
+; CHECK-NEXT: call void @f() #[[ATTR0:[0-9]+]]
; CHECK-NEXT: invoke void @f()
; CHECK-NEXT: to label [[VIA_CATCHSWITCH:%.*]] unwind label [[CLEANUP_INNER:%.*]]
; CHECK: cleanup.inner:
@@ -155,5 +155,5 @@ exit:
ret void
}
;.
-; CHECK: attributes #[[ATTR0:[0-9]+]] = { nounwind }
+; CHECK: attributes #[[ATTR0]] = { nounwind }
;.
diff --git a/llvm/test/Transforms/SimplifyCFG/invoke_unwind.ll b/llvm/test/Transforms/SimplifyCFG/invoke_unwind.ll
index 32ec9b23ad2fe..7f47132f12d5f 100644
--- a/llvm/test/Transforms/SimplifyCFG/invoke_unwind.ll
+++ b/llvm/test/Transforms/SimplifyCFG/invoke_unwind.ll
@@ -7,7 +7,7 @@ declare void @bar()
; instructions to call instructions if the handler just rethrows the exception.
define i32 @test1() personality ptr @__gxx_personality_v0 {
; CHECK-LABEL: @test1(
-; CHECK-NEXT: call void @bar(), !prof [[PROF0:![0-9]+]]
+; CHECK-NEXT: call void @bar() #[[ATTR0:[0-9]+]], !prof [[PROF0:![0-9]+]]
; CHECK-NEXT: ret i32 0
;
invoke void @bar( )
@@ -23,7 +23,7 @@ Rethrow:
define i32 @test2() personality ptr @__gxx_personality_v0 {
; CHECK-LABEL: @test2(
-; CHECK-NEXT: call void @bar() [ "foo"(i32 100) ]
+; CHECK-NEXT: call void @bar() #[[ATTR0]] [ "foo"(i32 100) ]
; CHECK-NEXT: ret i32 0
;
invoke void @bar( ) [ "foo"(i32 100) ]
@@ -46,10 +46,10 @@ define i64 @test3(i1 %cond) personality ptr @__gxx_personality_v0 {
; CHECK-NEXT: entry:
; CHECK-NEXT: br i1 [[COND:%.*]], label [[BR1:%.*]], label [[BR2:%.*]]
; CHECK: br1:
-; CHECK-NEXT: [[CALL1:%.*]] = call i64 @dummy1()
+; CHECK-NEXT: [[CALL1:%.*]] = call i64 @dummy1() #[[ATTR0]]
; CHECK-NEXT: br label [[INVOKE_CONT:%.*]]
; CHECK: br2:
-; CHECK-NEXT: [[CALL2:%.*]] = call i64 @dummy2()
+; CHECK-NEXT: [[CALL2:%.*]] = call i64 @dummy2() #[[ATTR0]]
; CHECK-NEXT: br label [[INVOKE_CONT]]
; CHECK: invoke.cont:
; CHECK-NEXT: [[C:%.*]] = phi i64 [ [[CALL1]], [[BR1]] ], [ [[CALL2]], [[BR2]] ]
@@ -88,5 +88,7 @@ lpad2:
declare i32 @__gxx_personality_v0(...)
;.
+; CHECK: attributes #[[ATTR0]] = { nounwind }
+;.
; CHECK: [[PROF0]] = !{!"branch_weights", i32 371}
;.
diff --git a/llvm/test/Transforms/SimplifyCFG/invoke_unwind_lifetime.ll b/llvm/test/Transforms/SimplifyCFG/invoke_unwind_lifetime.ll
index ff031e95bc042..d9d845a66d7a6 100644
--- a/llvm/test/Transforms/SimplifyCFG/invoke_unwind_lifetime.ll
+++ b/llvm/test/Transforms/SimplifyCFG/invoke_unwind_lifetime.ll
@@ -28,10 +28,10 @@ define void @caller(i1 %c) personality ptr @__gxx_personality_v0 {
; CHECK-NEXT: call void @escape(ptr [[I6]])
; CHECK-NEXT: br i1 [[C:%.*]], label [[V0:%.*]], label [[V1:%.*]]
; CHECK: v0:
-; CHECK-NEXT: call void @throwing_callee_foo()
+; CHECK-NEXT: call void @throwing_callee_foo() #[[ATTR1:[0-9]+]]
; CHECK-NEXT: unreachable
; CHECK: v1:
-; CHECK-NEXT: call void @throwing_callee_bar()
+; CHECK-NEXT: call void @throwing_callee_bar() #[[ATTR1]]
; CHECK-NEXT: unreachable
;
entry:
@@ -82,4 +82,5 @@ end:
}
;.
; CHECK: attributes #[[ATTR0:[0-9]+]] = { nocallback nofree nosync nounwind willreturn memory(argmem: readwrite) }
+; CHECK: attributes #[[ATTR1]] = { nounwind }
;.
diff --git a/llvm/test/Transforms/SimplifyCFG/lifetime-landingpad.ll b/llvm/test/Transforms/SimplifyCFG/lifetime-landingpad.ll
index 0174eb149581c..1bb405b9af020 100644
--- a/llvm/test/Transforms/SimplifyCFG/lifetime-landingpad.ll
+++ b/llvm/test/Transforms/SimplifyCFG/lifetime-landingpad.ll
@@ -6,7 +6,7 @@ define void @foo() personality ptr @__gxx_personality_v0 {
; CHECK-NEXT: entry:
; CHECK-NEXT: [[A:%.*]] = alloca i8, align 1
; CHECK-NEXT: call void @llvm.lifetime.start.p0(i64 1, ptr nonnull [[A]]) #[[ATTR1:[0-9]+]]
-; CHECK-NEXT: call void @bar()
+; CHECK-NEXT: call void @bar() #[[ATTR1]]
; CHECK-NEXT: call void @llvm.lifetime.end.p0(i64 1, ptr nonnull [[A]]) #[[ATTR1]]
; CHECK-NEXT: ret void
;
diff --git a/llvm/test/Transforms/SimplifyCFG/wineh-unreachable.ll b/llvm/test/Transforms/SimplifyCFG/wineh-unreachable.ll
index 9828db2a69853..0d495f95afe6e 100644
--- a/llvm/test/Transforms/SimplifyCFG/wineh-unreachable.ll
+++ b/llvm/test/Transforms/SimplifyCFG/wineh-unreachable.ll
@@ -7,7 +7,7 @@ declare void @f()
define void @test1() personality ptr @Personality {
; CHECK-LABEL: @test1(
; CHECK-NEXT: entry:
-; CHECK-NEXT: call void @f()
+; CHECK-NEXT: call void @f() #[[ATTR0:[0-9]+]]
; CHECK-NEXT: ret void
;
entry:
@@ -61,7 +61,7 @@ define void @test3() personality ptr @Personality {
; CHECK-NEXT: to label [[EXIT:%.*]] unwind label [[CLEANUP_PAD:%.*]]
; CHECK: cleanup.pad:
; CHECK-NEXT: [[CLEANUP:%.*]] = cleanuppad within none []
-; CHECK-NEXT: call void @f()
+; CHECK-NEXT: call void @f() #[[ATTR0]]
; CHECK-NEXT: unreachable
; CHECK: exit:
; CHECK-NEXT: ret void
@@ -238,3 +238,6 @@ catch.body2:
exit:
ret void
}
+;.
+; CHECK: attributes #[[ATTR0]] = { nounwind }
+;.
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