llvm-6502/test/Transforms/InstCombine/badmalloc.ll
Nuno Lopes 9969458b16 teach instcombine to remove allocated buffers even if there are stores, memcpy/memmove/memset, and objectsize users.
This means we can do cheap DSE for heap memory.
Nothing is done if the pointer excapes or has a load.

The churn in the tests is mostly due to objectsize, since we want to make sure we
don't delete the malloc call before evaluating the objectsize (otherwise it becomes -1/0)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159876 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-06 23:09:25 +00:00

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LLVM

; RUN: opt < %s -instcombine -S | FileCheck %s
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"
target triple = "x86_64-apple-darwin10.0"
declare noalias i8* @malloc(i64) nounwind
declare void @free(i8*)
; PR5130
define i1 @test1() {
%A = call noalias i8* @malloc(i64 4) nounwind
%B = icmp eq i8* %A, null
store i8 0, i8* %A
call void @free(i8* %A)
ret i1 %B
; CHECK: @test1
; CHECK: ret i1 false
}
; CHECK: @test2
define noalias i8* @test2() nounwind {
entry:
; CHECK: @malloc
%A = call noalias i8* @malloc(i64 4) nounwind
; CHECK: icmp eq
%tobool = icmp eq i8* %A, null
; CHECK: br i1
br i1 %tobool, label %return, label %if.end
if.end:
; CHECK: store
store i8 7, i8* %A
br label %return
return:
; CHECK: phi
%retval.0 = phi i8* [ %A, %if.end ], [ null, %entry ]
ret i8* %retval.0
}