llvm/test/Transforms/DeadStoreElimination/calloc-store.ll
Igor Laevsky ebe9301ae1 [DeadStoreElimination] Remove dead zero store to calloc initialized memory
This change allows dead store elimination to remove zero and null stores into memory freshly allocated with calloc-like function.

Differential Revision: http://reviews.llvm.org/D13021



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@248374 91177308-0d34-0410-b5e6-96231b3b80d8
2015-09-23 11:38:44 +00:00

66 lines
1.6 KiB
LLVM

; RUN: opt < %s -basicaa -dse -S | FileCheck %s
declare noalias i8* @calloc(i64, i64)
define i32* @test1() {
; CHECK-LABEL: test1
%1 = tail call noalias i8* @calloc(i64 1, i64 4)
%2 = bitcast i8* %1 to i32*
; This store is dead and should be removed
store i32 0, i32* %2, align 4
; CHECK-NOT: store i32 0, i32* %2, align 4
ret i32* %2
}
define i32* @test2() {
; CHECK-LABEL: test2
%1 = tail call noalias i8* @calloc(i64 1, i64 4)
%2 = bitcast i8* %1 to i32*
%3 = getelementptr i32, i32* %2, i32 5
store i32 0, i32* %3, align 4
; CHECK-NOT: store i32 0, i32* %2, align 4
ret i32* %2
}
define i32* @test3(i32 *%arg) {
; CHECK-LABEL: test3
store i32 0, i32* %arg, align 4
; CHECK: store i32 0, i32* %arg, align 4
ret i32* %arg
}
declare void @clobber_memory(i8*)
define i8* @test4() {
; CHECK-LABEL: test4
%1 = tail call noalias i8* @calloc(i64 1, i64 4)
call void @clobber_memory(i8* %1)
store i8 0, i8* %1, align 4
; CHECK: store i8 0, i8* %1, align 4
ret i8* %1
}
define i32* @test5() {
; CHECK-LABEL: test5
%1 = tail call noalias i8* @calloc(i64 1, i64 4)
%2 = bitcast i8* %1 to i32*
store volatile i32 0, i32* %2, align 4
; CHECK: store volatile i32 0, i32* %2, align 4
ret i32* %2
}
define i8* @test6() {
; CHECK-LABEL: test6
%1 = tail call noalias i8* @calloc(i64 1, i64 4)
store i8 5, i8* %1, align 4
; CHECK: store i8 5, i8* %1, align 4
ret i8* %1
}
define i8* @test7(i8 %arg) {
; CHECK-LABEL: test7
%1 = tail call noalias i8* @calloc(i64 1, i64 4)
store i8 %arg, i8* %1, align 4
; CHECK: store i8 %arg, i8* %1, align 4
ret i8* %1
}