From: Richard Kenner <kenner@gcc.gnu.org>
Date: Sat, 2 Oct 1993 18:10:47 +0000 (-0400)
Subject: (can_combine_p): Allow an insn with a REG_EQUIV note that reads memory
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=d81481d3d95364ece0e95fb8d0373bef2e55f50d;p=gcc.git

(can_combine_p): Allow an insn with a REG_EQUIV note that reads memory
to be moved past an insn that writes memory.

From-SVN: r5562
---

diff --git a/gcc/combine.c b/gcc/combine.c
index 45d572a7add..c50265681b0 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -855,10 +855,14 @@ can_combine_p (insn, i3, pred, succ, pdest, psrc)
 	 If the insns are adjacent, a use can't cross a set even though we
 	 think it might (this can happen for a sequence of insns each setting
 	 the same destination; reg_last_set of that register might point to
-	 a NOTE).  Also, don't move a volatile asm or UNSPEC_VOLATILE across
-	 any other insns.  */
+	 a NOTE).  If INSN has a REG_EQUIV note, the register is always
+	 equivalent to the memory so the substitution is valid even if there
+	 are intervening stores.  Also, don't move a volatile asm or
+	 UNSPEC_VOLATILE across any other insns.  */
       || (! all_adjacent
-	  && (use_crosses_set_p (src, INSN_CUID (insn))
+	  && (((GET_CODE (src) != MEM
+		|| ! find_reg_note (insn, REG_EQUIV, src))
+	       && use_crosses_set_p (src, INSN_CUID (insn)))
 	      || (GET_CODE (src) == ASM_OPERANDS && MEM_VOLATILE_P (src))
 	      || GET_CODE (src) == UNSPEC_VOLATILE))
       /* If there is a REG_NO_CONFLICT note for DEST in I3 or SUCC, we get