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https://github.com/c64scene-ar/llvm-6502.git
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6bde9f6994
This patch tries to merge duplicate landing pads when they branch to a common shared target.
Given IR that looks like this:
lpad1:
%exn = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0
cleanup
br label %shared_resume
lpad2:
%exn2 = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0
cleanup
br label %shared_resume
shared_resume:
call void @fn()
ret void
}
We can rewrite the users of both landing pad blocks to use one of them. This will generally allow the shared_resume block to be merged with the common landing pad as well.
Without this change, tail duplication would likely kick in - creating N (2 in this case) copies of the shared_resume basic block.
Differential Revision: http://reviews.llvm.org/D8297
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@233125 91177308-0d34-0410-b5e6-96231b3b80d8
111 lines
2.6 KiB
LLVM
111 lines
2.6 KiB
LLVM
; RUN: opt < %s -simplifycfg -S | FileCheck %s
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target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
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declare i32 @__gxx_personality_v0(...)
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declare void @fn()
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; CHECK-LABEL: @test1
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define void @test1() {
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entry:
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; CHECK-LABEL: entry:
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; CHECK: to label %invoke2 unwind label %lpad2
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invoke void @fn()
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to label %invoke2 unwind label %lpad1
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invoke2:
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; CHECK-LABEL: invoke2:
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; CHECK: to label %invoke.cont unwind label %lpad2
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invoke void @fn()
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to label %invoke.cont unwind label %lpad2
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invoke.cont:
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ret void
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lpad1:
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%exn = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0
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cleanup
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br label %shared_resume
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lpad2:
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; CHECK-LABEL: lpad2:
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; CHECK: landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
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; CHECK-NEXT: cleanup
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; CHECK-NEXT: call void @fn()
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; CHECK-NEXT: ret void
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%exn2 = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0
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cleanup
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br label %shared_resume
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shared_resume:
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call void @fn()
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ret void
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}
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; Don't trigger if blocks aren't the same/empty
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define void @neg1() {
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; CHECK-LABEL: @neg1
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entry:
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; CHECK-LABEL: entry:
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; CHECK: to label %invoke2 unwind label %lpad1
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invoke void @fn()
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to label %invoke2 unwind label %lpad1
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invoke2:
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; CHECK-LABEL: invoke2:
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; CHECK: to label %invoke.cont unwind label %lpad2
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invoke void @fn()
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to label %invoke.cont unwind label %lpad2
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invoke.cont:
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ret void
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lpad1:
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%exn = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0
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filter [0 x i8*] zeroinitializer
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call void @fn()
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br label %shared_resume
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lpad2:
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%exn2 = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0
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cleanup
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br label %shared_resume
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shared_resume:
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call void @fn()
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ret void
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}
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; Should not trigger when the landing pads are not the exact same
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define void @neg2() {
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; CHECK-LABEL: @neg2
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entry:
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; CHECK-LABEL: entry:
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; CHECK: to label %invoke2 unwind label %lpad1
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invoke void @fn()
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to label %invoke2 unwind label %lpad1
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invoke2:
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; CHECK-LABEL: invoke2:
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; CHECK: to label %invoke.cont unwind label %lpad2
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invoke void @fn()
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to label %invoke.cont unwind label %lpad2
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invoke.cont:
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ret void
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lpad1:
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%exn = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0
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filter [0 x i8*] zeroinitializer
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br label %shared_resume
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lpad2:
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%exn2 = landingpad {i8*, i32} personality i32 (...)* @__gxx_personality_v0
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cleanup
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br label %shared_resume
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shared_resume:
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call void @fn()
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ret void
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}
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