commit abf953042ace471720c1dc284b5f38e546fc0595
Author: Vladimir N. Makarov <vmakarov@redhat.com>
Date: Fri Aug 4 08:04:44 2023 -0400
LRA: Check input insn pattern hard regs against early clobber hard regs for live info
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.
@@ -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)
new file mode 100644
@@ -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" } } */