We've had Thumb1 support for ARMISD::SUBE for a while now, so this just
works. Reduces codesize a bit for 64-bit integer comparisons.
Differential Revision: https://reviews.llvm.org/D47387
llvm-svn: 333445
When expanding a BRCOND into a BR_CC, do not create an AND 1
if one already exists.
Review: D36705
Patch by Joel Galenson <jgalenson@google.com>
llvm-svn: 311447
The ARM backend should call setBooleanContents so that it can
use known bits to make some optimizations.
Review: D35821
Patch by Joel Galenson <jgalenson@google.com>
llvm-svn: 311446
This introduces a custom lowering for ISD::SETCCE (introduced in r253572)
that allows us to emit a short code sequence for 64-bit compares.
Before:
push {r7, lr}
cmp r0, r2
mov.w r0, #0
mov.w r12, #0
it hs
movhs r0, #1
cmp r1, r3
it ge
movge.w r12, #1
it eq
moveq r12, r0
cmp.w r12, #0
bne .LBB1_2
@ BB#1: @ %bb1
bl f
pop {r7, pc}
.LBB1_2: @ %bb2
bl g
pop {r7, pc}
After:
push {r7, lr}
subs r0, r0, r2
sbcs.w r0, r1, r3
bge .LBB1_2
@ BB#1: @ %bb1
bl f
pop {r7, pc}
.LBB1_2: @ %bb2
bl g
pop {r7, pc}
Saves around 80KB in Chromium's libchrome.so.
Some notes on this patch:
- I don't much like the ARMISD::BRCOND and ARMISD::CMOV combines I
introduced (nothing else needs them). However, they are necessary in
order to avoid poor codegen, and they seem similar to existing combines
in other backends (e.g. X86 combines (brcond (cmp (setcc Compare))) to
(brcond Compare)).
- No support for Thumb-1. This is in principle possible, but we'd need
to implement ARMISD::SUBE for Thumb-1.
Differential Revision: http://reviews.llvm.org/D15256
llvm-svn: 263962
Eli Friedman