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[DSE,MSSA] Recognise init_trampoline in getLocForWriteEx 

This fixes an instance where MemorySSA-using Dead Store Elimination is failing
to do a transformation that the non-MemorySSA-using version does.

Differential Revision: https://reviews.llvm.org/D83783
This commit is contained in:
John Brawn 2020-07-15 12:17:31 +01:00
parent a9e10a0965
commit 20854d85e1
3 changed files with 18 additions and 23 deletions
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6
llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
View File

@ -1593,6 +1593,12 @@ struct DSEState {
break;
}
}
switch (CB->getIntrinsicID()) {
case Intrinsic::init_trampoline:
return {MemoryLocation(CB->getArgOperand(0))};
default:
break;
}
return None;
}

23
llvm/test/Transforms/DeadStoreElimination/MSSA/simple-todo.ll
View File

@ -4,29 +4,6 @@
; RUN: opt < %s -aa-pipeline=basic-aa -passes=dse -enable-dse-memoryssa -S | FileCheck %s
target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i1) nounwind
declare void @llvm.memset.element.unordered.atomic.p0i8.i64(i8* nocapture, i8, i64, i32) nounwind
declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i1) nounwind
declare void @llvm.memcpy.element.unordered.atomic.p0i8.p0i8.i64(i8* nocapture, i8* nocapture, i64, i32) nounwind
declare void @llvm.init.trampoline(i8*, i8*, i8*)
; DSE should delete the dead trampoline.
declare void @test11f()
define void @test11() {
; CHECK-LABEL: @test11(
; CHECK-NEXT: ret void
;
%storage = alloca [10 x i8], align 16 ; <[10 x i8]*> [#uses=1]
%cast = getelementptr [10 x i8], [10 x i8]* %storage, i32 0, i32 0 ; <i8*> [#uses=1]
call void @llvm.init.trampoline( i8* %cast, i8* bitcast (void ()* @test11f to i8*), i8* null ) ; <i8*> [#uses=1]
ret void
}
declare noalias i8* @malloc(i32)
declare void @unknown_func()
; Remove redundant store if loaded value is in another block inside a loop.
define i32 @test31(i1 %c, i32* %p, i32 %i) {
; CHECK-LABEL: @test31(

12
llvm/test/Transforms/DeadStoreElimination/MSSA/simple.ll
View File

@ -181,6 +181,18 @@ define double @test10(i8* %X) {
ret double %tmp.0
}
; DSE should delete the dead trampoline.
declare void @test11f()
define void @test11() {
; CHECK-LABEL: @test11(
; CHECK-NEXT: ret void
;
%storage = alloca [10 x i8], align 16 ; <[10 x i8]*> [#uses=1]
%cast = getelementptr [10 x i8], [10 x i8]* %storage, i32 0, i32 0 ; <i8*> [#uses=1]
call void @llvm.init.trampoline( i8* %cast, i8* bitcast (void ()* @test11f to i8*), i8* null ) ; <i8*> [#uses=1]
ret void
}
; %P doesn't escape, the DEAD instructions should be removed.
declare void @test13f()
define i32* @test13() {