From: konglin1 <lingling.kong@intel.com>
Date: Thu, 9 May 2024 01:48:56 +0000 (+0800)
Subject: i386: fix ix86_hardreg_mov_ok with lra_in_progress
X-Git-Tag: basepoints/gcc-16~9219
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=baf1a677955a4dcfffe8d93966900af96600d642;p=thirdparty%2Fgcc.git

i386: fix ix86_hardreg_mov_ok with lra_in_progress

Originally eliminate_regs_in_insnit will transform
(parallel [
  (set (reg:QI 130)
    (plus:QI (subreg:QI (reg:DI 19 frame) 0)
      (const_int 96)))
  (clobber (reg:CC 17 flag))]) {*addqi_1}
to
(set (reg:QI 130)
 (subreg:QI (reg:DI 19 frame) 0)) {*movqi_internal}
when verify_changes.

But with No Flags add, it transforms
(set (reg:QI 5 di)
  (plus:QI (subreg:QI (reg:DI 19 frame) 0)
   (const_int 96))) {*addqi_1_nf}
to
(set (reg:QI 5 di)
 (subreg:QI (reg:DI 19 frame) 0)) {*addqi_1_nf}.
there is no extra clobbers at the end, and
its dest reg just is a hardreg. For ix86_hardreg_mov_ok,
it returns false. So it fails to update insn and causes
the ICE when transform to movqi_internal.

But actually it is ok and safe for ix86_hardreg_mov_ok
when lra_in_progress.

And tested the spec2017, the performance was not affected.

gcc/ChangeLog:

	* config/i386/i386.cc (ix86_hardreg_mov_ok): Relax
	hard reg mov restriction when lra in progress.
---

diff --git a/gcc/config/i386/i386.cc b/gcc/config/i386/i386.cc
index c2df4ab91ee..54c6c445bf1 100644
--- a/gcc/config/i386/i386.cc
+++ b/gcc/config/i386/i386.cc
@@ -20355,7 +20355,8 @@ ix86_hardreg_mov_ok (rtx dst, rtx src)
 	   ? standard_sse_constant_p (src, GET_MODE (dst))
 	   : x86_64_immediate_operand (src, GET_MODE (dst)))
       && ix86_class_likely_spilled_p (REGNO_REG_CLASS (REGNO (dst)))
-      && !reload_completed)
+      && !reload_completed
+      && !lra_in_progress)
     return false;
   return true;
 }