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author | Reid Kleckner <reid@kleckner.net> | 2014-05-15 21:10:46 +0000 |
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committer | Reid Kleckner <reid@kleckner.net> | 2014-05-15 21:10:46 +0000 |
commit | 48ea98d1d228dfc58f9662473a4253c052c44b03 (patch) | |
tree | c9ac261563698d551e1f7db7e438746d34045617 | |
parent | cf7cfd8208f2ca52e86a9c0fb1fa73d1f5b553e3 (diff) | |
download | llvm-48ea98d1d228dfc58f9662473a4253c052c44b03.tar.gz llvm-48ea98d1d228dfc58f9662473a4253c052c44b03.tar.bz2 llvm-48ea98d1d228dfc58f9662473a4253c052c44b03.tar.xz |
Don't insert lifetime.end markers between a musttail call and ret
The allocas going out of scope are immediately killed by the return
instruction.
This is a resend of r208912, which was committed accidentally.
Reviewers: chandlerc
Differential Revision: http://reviews.llvm.org/D3792
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@208920 91177308-0d34-0410-b5e6-96231b3b80d8
-rw-r--r-- | lib/Transforms/Utils/InlineFunction.cpp | 14 | ||||
-rw-r--r-- | test/Transforms/Inline/inline-tail.ll | 36 |
2 files changed, 48 insertions, 2 deletions
diff --git a/lib/Transforms/Utils/InlineFunction.cpp b/lib/Transforms/Utils/InlineFunction.cpp index ab60a400e5..e01d0c38ec 100644 --- a/lib/Transforms/Utils/InlineFunction.cpp +++ b/lib/Transforms/Utils/InlineFunction.cpp @@ -755,8 +755,13 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI, } builder.CreateLifetimeStart(AI, AllocaSize); - for (ReturnInst *RI : Returns) + for (ReturnInst *RI : Returns) { + // Don't insert llvm.lifetime.end calls between a musttail call and a + // return. The return kills all local allocas. + if (InlinedMustTailCalls && getPrecedingMustTailCall(RI)) + continue; IRBuilder<>(RI).CreateLifetimeEnd(AI, AllocaSize); + } } } @@ -774,8 +779,13 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI, // Insert a call to llvm.stackrestore before any return instructions in the // inlined function. - for (ReturnInst *RI : Returns) + for (ReturnInst *RI : Returns) { + // Don't insert llvm.stackrestore calls between a musttail call and a + // return. The return will restore the stack pointer. + if (InlinedMustTailCalls && getPrecedingMustTailCall(RI)) + continue; IRBuilder<>(RI).CreateCall(StackRestore, SavedPtr); + } } // If we are inlining for an invoke instruction, we must make sure to rewrite diff --git a/test/Transforms/Inline/inline-tail.ll b/test/Transforms/Inline/inline-tail.ll index 565491adf5..b40328e0a2 100644 --- a/test/Transforms/Inline/inline-tail.ll +++ b/test/Transforms/Inline/inline-tail.ll @@ -49,6 +49,42 @@ define void @test_musttail_basic_a(i32* %p) { ret void } +; Don't insert lifetime end markers here, the lifetime is trivially over due +; the return. +; CHECK: define void @test_byval_a( +; CHECK: musttail call void @test_byval_c( +; CHECK-NEXT: ret void + +declare void @test_byval_c(i32* byval %p) +define internal void @test_byval_b(i32* byval %p) { + musttail call void @test_byval_c(i32* byval %p) + ret void +} +define void @test_byval_a(i32* byval %p) { + musttail call void @test_byval_b(i32* byval %p) + ret void +} + +; Don't insert a stack restore, we're about to return. +; CHECK: define void @test_dynalloca_a( +; CHECK: call i8* @llvm.stacksave( +; CHECK: alloca i8, i32 %n +; CHECK: musttail call void @test_dynalloca_c( +; CHECK-NEXT: ret void + +declare void @escape(i8* %buf) +declare void @test_dynalloca_c(i32* byval %p, i32 %n) +define internal void @test_dynalloca_b(i32* byval %p, i32 %n) alwaysinline { + %buf = alloca i8, i32 %n ; dynamic alloca + call void @escape(i8* %buf) ; escape it + musttail call void @test_dynalloca_c(i32* byval %p, i32 %n) + ret void +} +define void @test_dynalloca_a(i32* byval %p, i32 %n) { + musttail call void @test_dynalloca_b(i32* byval %p, i32 %n) + ret void +} + ; We can't merge the returns. ; CHECK: define void @test_multiret_a( ; CHECK: musttail call void @test_multiret_c( |