File: calloc-load-removal.ll

package info (click to toggle)
llvm-toolchain-11 1%3A11.0.1-2
  • links: PTS, VCS
  • area: main
  • in suites: bullseye
  • size: 995,808 kB
  • sloc: cpp: 4,767,656; ansic: 760,916; asm: 477,436; python: 170,940; objc: 69,804; lisp: 29,914; sh: 23,855; f90: 18,173; pascal: 7,551; perl: 7,471; ml: 5,603; awk: 3,489; makefile: 2,573; xml: 915; cs: 573; fortran: 503; javascript: 452
file content (25 lines) | stat: -rw-r--r-- 843 bytes parent folder | download | duplicates (5) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
 
; RUN: opt -S -basic-aa -newgvn < %s | FileCheck %s
; RUN: opt -S -basic-aa -newgvn -disable-simplify-libcalls < %s | FileCheck %s -check-prefix=CHECK_NO_LIBCALLS
; Check that loads from calloc are recognized as being zero.

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"

; Function Attrs: nounwind uwtable
define i32 @test1() {
  %1 = tail call noalias i8* @calloc(i64 1, i64 4)
  %2 = bitcast i8* %1 to i32*
  ; This load is trivially constant zero
  %3 = load i32, i32* %2, align 4
  ret i32 %3

; CHECK-LABEL: @test1(
; CHECK-NOT: %3 = load i32, i32* %2, align 4
; CHECK: ret i32 0

; CHECK_NO_LIBCALLS-LABEL: @test1(
; CHECK_NO_LIBCALLS: load
; CHECK_NO_LIBCALLS: ret i32 %

}

declare noalias i8* @calloc(i64, i64)