From: Martin Liska <mliska@suse.cz>
Date: Sun, 18 Mar 2018 20:17:10 +0000 (+0100)
Subject: Fix UBSAN in regrename.c (PR rtl-optimization/84635).
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=f7dbf8e56459916a66af9fc62608109f65babd51;p=gcc.git

Fix UBSAN in regrename.c (PR rtl-optimization/84635).

2018-03-18  Martin Liska  <mliska@suse.cz>

	PR rtl-optimization/84635
	* regrename.c (build_def_use): Use matches_mode only when
	matches >= 0.

From-SVN: r258634
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 2a77e3b9245..9aab6e606d4 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-03-18  Martin Liska  <mliska@suse.cz>
+
+	PR rtl-optimization/84635
+	* regrename.c (build_def_use): Use matches_mode only when
+	matches >= 0.
+
 2018-03-18  Richard Sandiford  <richard.sandiford@linaro.org>
 
 	PR tree-optimization/84913
diff --git a/gcc/regrename.c b/gcc/regrename.c
index dcec77adf75..45754812f6c 100644
--- a/gcc/regrename.c
+++ b/gcc/regrename.c
@@ -1703,14 +1703,18 @@ build_def_use (basic_block bb)
 		     and we must instead make sure to make the operand visible
 		     to the machinery that tracks hard registers.  */
 		  machine_mode i_mode = recog_data.operand_mode[i];
-		  machine_mode matches_mode = recog_data.operand_mode[matches];
-		  if (matches >= 0
-		      && maybe_ne (GET_MODE_SIZE (i_mode),
-				   GET_MODE_SIZE (matches_mode))
-		      && !verify_reg_in_set (op, &live_in_chains))
+		  if (matches >= 0)
 		    {
-		      untracked_operands |= 1 << i;
-		      untracked_operands |= 1 << matches;
+		      machine_mode matches_mode
+			= recog_data.operand_mode[matches];
+
+		      if (maybe_ne (GET_MODE_SIZE (i_mode),
+				    GET_MODE_SIZE (matches_mode))
+			  && !verify_reg_in_set (op, &live_in_chains))
+			{
+			  untracked_operands |= 1 << i;
+			  untracked_operands |= 1 << matches;
+			}
 		    }
 		}
 #ifdef STACK_REGS