From: Vladimir N. Makarov <vmakarov@redhat.com>
Date: Wed, 29 Apr 2026 13:37:11 +0000 (-0400)
Subject: [LRA]: Fix a bug in updating live info in rematerialization
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ef039a5bf888f736eb4504fe1322b8c1d5523dea;p=thirdparty%2Fgcc.git

[LRA]: Fix a bug in updating live info in rematerialization

LRA rematerialization ignores that a pseudo can require more one hard reg
when updating live hard reg info.  This can result in wrong
rematerialization. The patch fixes this.

gcc/ChangeLog:

	* lra-remat.cc (do_remat): Use the right nregs for pseudo hard reg
	when updating live hard regs.
---

diff --git a/gcc/lra-remat.cc b/gcc/lra-remat.cc
index c4da3f75e59..20d9f47d2e9 100644
--- a/gcc/lra-remat.cc
+++ b/gcc/lra-remat.cc
@@ -1073,11 +1073,17 @@ do_remat (void)
       CLEAR_HARD_REG_SET (live_hard_regs);
       EXECUTE_IF_SET_IN_BITMAP (df_get_live_in (bb), 0, regno, bi)
 	{
-	  int hard_regno = regno < FIRST_PSEUDO_REGISTER
-			   ? regno
-			   : reg_renumber[regno];
-	  if (hard_regno >= 0)
-	    SET_HARD_REG_BIT (live_hard_regs, hard_regno);
+	  int nregs = 1;
+	  int hard_regno = regno;
+	  if (regno >= FIRST_PSEUDO_REGISTER)
+	    {
+	      hard_regno = reg_renumber[regno];
+	      if (hard_regno < 0)
+		continue;
+	      nregs = hard_regno_nregs (hard_regno, PSEUDO_REGNO_MODE (regno));
+	    }
+	  for (int i = 0; i < nregs; i++)
+	    SET_HARD_REG_BIT (live_hard_regs, hard_regno + i);
 	}
       bitmap_and (avail_cands, &get_remat_bb_data (bb)->avin_cands,
 		  &get_remat_bb_data (bb)->livein_cands);