FreeChainXenon/gcc
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

[RA]: Fixing LRA cycling for multi-reg variable containing a fixed reg

Browse source 
PR111971 test case uses a multi-reg variable containing a fixed reg.  LRA
rejects such multi-reg because of this when matching the constraint for
an asm insn.  The rejection results in LRA cycling.  The patch fixes this issue.

gcc/ChangeLog:

	PR rtl-optimization/111971
	* lra-constraints.cc: (process_alt_operands): Don't check start
	hard regs for regs originated from register variables.

gcc/testsuite/ChangeLog:

	PR rtl-optimization/111971
	* gcc.target/powerpc/pr111971.c: New test.
This commit is contained in:
Vladimir N. Makarov 2023-10-31 10:54:43 -04:00
parent 3e888f9462
commit 9119b008b4
2 changed files with 16 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

9
gcc/lra-constraints.cc
View file

@ -2609,12 +2609,15 @@ process_alt_operands (int only_alternative)
winreg = true;
if (REG_P (op))
{
tree decl;
if (hard_regno[nop] >= 0
&& in_hard_reg_set_p (this_alternative_set,
mode, hard_regno[nop])
&& !TEST_HARD_REG_BIT
(this_alternative_exclude_start_hard_regs,
hard_regno[nop]))
&& ((REG_ATTRS (op) && (decl = REG_EXPR (op)) != NULL
&& VAR_P (decl) && DECL_HARD_REGISTER (decl))
|| !(TEST_HARD_REG_BIT
(this_alternative_exclude_start_hard_regs,
hard_regno[nop]))))
win = true;
else if (hard_regno[nop] < 0
&& in_class_p (op, this_alternative, NULL))

10
gcc/testsuite/gcc.target/powerpc/pr111971.c Normal file
View file

@ -0,0 +1,10 @@
/* { dg-do compile } */
/* { dg-options "-O2" } */
void
foo (unsigned long long *a)
{
register long long d asm ("r0") = 0x24;
long long n;
asm ("mr %0, %1" : "=r"(n) : "r"(d));
*a++ = n;
}