llvm/test/Transforms/InstCombine/builtin-object-size-ptr.ll
Petar Jovanovic 6ed4786900 Reland r262337 "calculate builtin_object_size if arg is a removable pointer"
Original commit message:
 calculate builtin_object_size if argument is a removable pointer

 This patch fixes calculating correct value for builtin_object_size function
 when pointer is used only in builtin_object_size function call and never
 after that.

 Patch by Strahinja Petrovic.

 Differential Revision: http://reviews.llvm.org/D17337

Reland the original change with a small modification (first do a null check
and then do the cast) to satisfy ubsan.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263011 91177308-0d34-0410-b5e6-96231b3b80d8
2016-03-09 14:12:47 +00:00

35 lines
979 B
LLVM

; RUN: opt -instcombine -S < %s | FileCheck %s
; int foo() {
; struct V { char buf1[10];
; int b;
; char buf2[10];
; } var;
;
; char *p = &var.buf1[1];
; return __builtin_object_size (p, 0);
; }
%struct.V = type { [10 x i8], i32, [10 x i8] }
define i32 @foo() #0 {
entry:
%var = alloca %struct.V, align 4
%0 = bitcast %struct.V* %var to i8*
call void @llvm.lifetime.start(i64 28, i8* %0) #3
%buf1 = getelementptr inbounds %struct.V, %struct.V* %var, i32 0, i32 0
%arrayidx = getelementptr inbounds [10 x i8], [10 x i8]* %buf1, i64 0, i64 1
%1 = call i64 @llvm.objectsize.i64.p0i8(i8* %arrayidx, i1 false)
%conv = trunc i64 %1 to i32
call void @llvm.lifetime.end(i64 28, i8* %0) #3
ret i32 %conv
; CHECK: ret i32 27
; CHECK-NOT: ret i32 -1
}
declare void @llvm.lifetime.start(i64, i8* nocapture) #1
declare i64 @llvm.objectsize.i64.p0i8(i8*, i1) #2
declare void @llvm.lifetime.end(i64, i8* nocapture) #1