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LRA: Check input insn pattern hard regs against early clobber hard regs for live info

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For the test case LRA generates wrong code for AVR cpymem_qi insn:

	(insn 16 15 17 3 (parallel [
            (set (mem:BLK (reg:HI 26 r26) [0  A8])
                (mem:BLK (reg:HI 30 r30) [0  A8]))
            (unspec [
                    (const_int 0 [0])
                ] UNSPEC_CPYMEM)
            (use (reg:QI 52))
            (clobber (reg:HI 26 r26))
            (clobber (reg:HI 30 r30))
            (clobber (reg:QI 0 r0))
            (clobber (reg:QI 52))
        ]) "t.c":16:22 132 {cpymem_qi}

The insn gets the same value in r26 and r30.  The culprit is clobbering
r30 and using r30 as input.  For such situation LRA wrongly assumes that
r30 does not live before the insn.  The patch is fixing it.

gcc/ChangeLog:

	* lra-lives.cc (process_bb_lives): Check input insn pattern hard regs
	against early clobber hard regs.

gcc/testsuite/ChangeLog:

	* gcc.target/avr/lra-cpymem_qi.c: New.
This commit is contained in:
Vladimir N. Makarov 2023-08-04 08:04:44 -04:00
parent 046640f9e5
commit abf953042a
2 changed files with 27 additions and 1 deletions
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2
gcc/lra-lives.cc
View file

@ -989,7 +989,7 @@ process_bb_lives (basic_block bb, int &curr_point, bool dead_insn_p)
/* We can have early clobbered non-operand hard reg and
the same hard reg as an insn input. Don't make hard
reg dead before the insns. */
for (reg2 = curr_id->regs; reg2 != NULL; reg2 = reg2->next)
for (reg2 = curr_static_id->hard_regs; reg2 != NULL; reg2 = reg2->next)
if (reg2->type != OP_OUT && reg2->regno == reg->regno)
break;
if (reg2 == NULL)

26
gcc/testsuite/gcc.target/avr/lra-cpymem_qi.c Normal file
View file

@ -0,0 +1,26 @@
/* { dg-do compile } */
/* { dg-options "-mmcu=avr51 -Os" } */
#include <stdbool.h>
struct A
{
unsigned int a;
unsigned char c1, c2;
bool b1 : 1;
};
void
foo (const struct A *x, int y)
{
int s = 0, i;
for (i = 0; i < y; ++i)
{
const struct A a = x[i];
s += a.b1 ? 1 : 0;
}
if (s != 0)
__builtin_abort ();
}
/* { dg-final { scan-assembler-not "movw\[^\n\r]*r26,r30" } } */