llvm/test/CodeGen/AArch64/subs-to-sub-opt.ll
Matthias Braun 773603e851 ScheduleDAGInstrs: Ignore dependencies of constant physregs
There is no need to track dependencies for constant physregs, as they
don't change their value no matter in what order you read/write to them.

Differential Revision: https://reviews.llvm.org/D26221

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286526 91177308-0d34-0410-b5e6-96231b3b80d8
2016-11-10 23:46:44 +00:00

24 lines
586 B
LLVM

; RUN: llc -mtriple=aarch64-linux-gnu -O3 -o - %s | FileCheck %s
@a = external global i8, align 1
@b = external global i8, align 1
; Test that SUBS is replaced by SUB if condition flags are not used.
define i32 @test01() nounwind {
; CHECK: ldrb {{.*}}
; CHECK-NEXT: ldrb {{.*}}
; CHECK: sub {{.*}}
; CHECK-NEXT: cmn {{.*}}
entry:
%0 = load i8, i8* @a, align 1
%conv = zext i8 %0 to i32
%1 = load i8, i8* @b, align 1
%conv1 = zext i8 %1 to i32
%s = sub nsw i32 %conv1, %conv
%cmp0 = icmp eq i32 %s, -1
%cmp1 = sext i1 %cmp0 to i8
store i8 %cmp1, i8* @a
ret i32 0
}