2014-04-04 00:01:44 +08:00
|
|
|
; RUN: llc -mtriple=arm-eabi -mcpu=cortex-a8 -asm-verbose=false %s -o - | FileCheck %s
|
DAG: Combine (and (setne X, 0), (setne X, -1)) -> (setuge (add X, 1), 2)
A common idiom is to use zero and all-ones as sentinal values and to
check for both in a single conditional ("x != 0 && x != (unsigned)-1").
That generates code, for i32, like:
testl %edi, %edi
setne %al
cmpl $-1, %edi
setne %cl
andb %al, %cl
With this transform, we generate the simpler:
incl %edi
cmpl $1, %edi
seta %al
Similar improvements for other integer sizes and on other platforms. In
general, combining the two setcc instructions into one is better.
rdar://14689217
llvm-svn: 188315
2013-08-14 05:30:58 +08:00
|
|
|
|
|
|
|
define zeroext i1 @test0(i32 %x) nounwind {
|
|
|
|
; CHECK-LABEL: test0:
|
2014-02-08 04:32:32 +08:00
|
|
|
; CHECK: add [[REG:(r[0-9]+)|(lr)]], r0, #1
|
DAG: Combine (and (setne X, 0), (setne X, -1)) -> (setuge (add X, 1), 2)
A common idiom is to use zero and all-ones as sentinal values and to
check for both in a single conditional ("x != 0 && x != (unsigned)-1").
That generates code, for i32, like:
testl %edi, %edi
setne %al
cmpl $-1, %edi
setne %cl
andb %al, %cl
With this transform, we generate the simpler:
incl %edi
cmpl $1, %edi
seta %al
Similar improvements for other integer sizes and on other platforms. In
general, combining the two setcc instructions into one is better.
rdar://14689217
llvm-svn: 188315
2013-08-14 05:30:58 +08:00
|
|
|
; CHECK-NEXT: mov r0, #0
|
|
|
|
; CHECK-NEXT: cmp [[REG]], #1
|
2013-08-22 17:57:11 +08:00
|
|
|
; CHECK-NEXT: movwhi r0, #1
|
DAG: Combine (and (setne X, 0), (setne X, -1)) -> (setuge (add X, 1), 2)
A common idiom is to use zero and all-ones as sentinal values and to
check for both in a single conditional ("x != 0 && x != (unsigned)-1").
That generates code, for i32, like:
testl %edi, %edi
setne %al
cmpl $-1, %edi
setne %cl
andb %al, %cl
With this transform, we generate the simpler:
incl %edi
cmpl $1, %edi
seta %al
Similar improvements for other integer sizes and on other platforms. In
general, combining the two setcc instructions into one is better.
rdar://14689217
llvm-svn: 188315
2013-08-14 05:30:58 +08:00
|
|
|
; CHECK-NEXT: bx lr
|
|
|
|
%cmp1 = icmp ne i32 %x, -1
|
|
|
|
%not.cmp = icmp ne i32 %x, 0
|
|
|
|
%.cmp1 = and i1 %cmp1, %not.cmp
|
|
|
|
ret i1 %.cmp1
|
|
|
|
}
|