From: Vladimir N. Makarov <vmakarov@redhat.com>
Date: Fri, 4 Aug 2023 12:04:44 +0000 (-0400)
Subject: LRA: Check input insn pattern hard regs	against early clobber hard regs	for live... 
X-Git-Tag: basepoints/gcc-15~7144
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=abf953042ace471720c1dc284b5f38e546fc0595;p=thirdparty%2Fgcc.git

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.
---

diff --git a/gcc/lra-lives.cc b/gcc/lra-lives.cc
index f7a3ba8d76a3..f60e564da82f 100644
--- a/gcc/lra-lives.cc
+++ b/gcc/lra-lives.cc
@@ -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)
diff --git a/gcc/testsuite/gcc.target/avr/lra-cpymem_qi.c b/gcc/testsuite/gcc.target/avr/lra-cpymem_qi.c
new file mode 100644
index 000000000000..fdffb445b454
--- /dev/null
+++ b/gcc/testsuite/gcc.target/avr/lra-cpymem_qi.c
@@ -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" } } */