llvm-6502/test/Transforms/InstCombine/objsize-64.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

40 lines
1.2 KiB
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-n8:16:32:64-S128"
declare noalias i8* @malloc(i32) nounwind
declare noalias i8* @_Znwm(i64) ; new(unsigned long)
declare i32 @__gxx_personality_v0(...)
declare void @__cxa_call_unexpected(i8*)
declare i64 @llvm.objectsize.i64(i8*, i1) nounwind readonly
; CHECK: @f1
define i64 @f1(i8 **%esc) {
%call = call i8* @malloc(i32 4)
store i8* %call, i8** %esc
%size = call i64 @llvm.objectsize.i64(i8* %call, i1 false)
; CHECK: ret i64 4
ret i64 %size
}
; CHECK: @f2
define i64 @f2(i8** %esc) nounwind uwtable ssp {
entry:
; CHECK: invoke noalias i8* @_Znwm(i64 13)
%call = invoke noalias i8* @_Znwm(i64 13)
to label %invoke.cont unwind label %lpad
invoke.cont:
; CHECK: ret i64 13
store i8* %call, i8** %esc
%0 = tail call i64 @llvm.objectsize.i64(i8* %call, i1 false)
ret i64 %0
lpad:
%1 = landingpad { i8*, i32 } personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*)
filter [0 x i8*] zeroinitializer
%2 = extractvalue { i8*, i32 } %1, 0
tail call void @__cxa_call_unexpected(i8* %2) noreturn nounwind
unreachable
}