From: Vladimir N. Makarov <vmakarov@redhat.com>
Date: Thu, 10 Mar 2022 21:16:00 +0000 (-0500)
Subject: [PR103074] LRA: Check new conflicts when splitting hard reg live range.
X-Git-Tag: basepoints/gcc-13~709
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d8e5fff6b74b82c2ac3254be9a1f0fb6b30dbdbf;p=thirdparty%2Fgcc.git

[PR103074] LRA: Check new conflicts when splitting hard reg live range.

Splitting hard register live range can create (artificial)
conflict of the hard register with another pseudo because of simplified
conflict calculation in LRA.  We should check such conflict on the next
assignment sub-pass and spill and reassign the pseudo if necessary.
The patch implements this.

gcc/ChangeLog:

	PR target/103074
	* lra-constraints.cc (split_reg): Set up
	check_and_force_assignment_correctness_p when splitting hard
	register live range.

gcc/testsuite/ChangeLog:

	PR target/103074
	* gcc.target/i386/pr103074.c: New.
---

diff --git a/gcc/lra-constraints.cc b/gcc/lra-constraints.cc
index 080b44ad87ab..d92ab76908c8 100644
--- a/gcc/lra-constraints.cc
+++ b/gcc/lra-constraints.cc
@@ -5994,12 +5994,17 @@ split_reg (bool before_p, int original_regno, rtx_insn *insn,
 			 before_p ? NULL : save,
 			 call_save_p
 			 ?  "Add save<-reg" : "Add split<-reg");
-  if (nregs > 1)
+  if (nregs > 1 || original_regno < FIRST_PSEUDO_REGISTER)
     /* If we are trying to split multi-register.  We should check
        conflicts on the next assignment sub-pass.  IRA can allocate on
        sub-register levels, LRA do this on pseudos level right now and
        this discrepancy may create allocation conflicts after
-       splitting.  */
+       splitting.
+
+       If we are trying to split hard register we should also check conflicts
+       as such splitting can create artificial conflict of the hard register
+       with another pseudo because of simplified conflict calculation in
+       LRA.  */
     check_and_force_assignment_correctness_p = true;
   if (lra_dump_file != NULL)
     fprintf (lra_dump_file,
diff --git a/gcc/testsuite/gcc.target/i386/pr103074.c b/gcc/testsuite/gcc.target/i386/pr103074.c
new file mode 100644
index 000000000000..276ad82a1de1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr103074.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-march=bonnell -Os -fPIC -fschedule-insns -w" } */
+
+void
+serialize_collection (char *ptr, int a, int need_owner)
+{
+  if (need_owner)
+    __builtin_sprintf(ptr, "%d:%d", 0, a);
+  else
+    {
+      static char buff[32];
+
+      __builtin_sprintf(buff, "%d:%d", a >> 32, a);
+      __builtin_sprintf(ptr, "%d:%d:\"%s\"", 0, 0, buff);
+    }
+}