From 6ee1791feeb4b8080daac0d21f9650e38e512b49 Mon Sep 17 00:00:00 2001
From: law <law@138bc75d-0d04-0410-961f-82ee72b054a4>
Date: Thu, 28 Mar 2002 23:33:52 +0000
Subject: [PATCH] * combine.c (simplify_and_const_int): Make sure to
apply mask when force_to_mode returns a constant integer. PR3311.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@51532 138bc75d-0d04-0410-961f-82ee72b054a4
---
gcc/ChangeLog | 5 +++++
gcc/combine.c | 17 +++++++++++++----
2 files changed, 18 insertions(+), 4 deletions(-)
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5a8d6fc9bcd2..a804219ef121 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+Thu Mar 28 16:35:31 2002 Jeffrey A Law (law@redhat.com)
+
+ * combine.c (simplify_and_const_int): Make sure to apply mask
+ when force_to_mode returns a constant integer. PR3311.
+
2002-03-28 John David Anglin <dave@hiauly1.hia.nrc.ca>
* pa-linux.h (LOCAL_LABEL_PREFIX): Define.
diff --git a/gcc/combine.c b/gcc/combine.c
index 0a61187071e4..adb034d80cab 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -7838,14 +7838,23 @@ simplify_and_const_int (x, mode, varop, constop)
int i;
/* Simplify VAROP knowing that we will be only looking at some of the
- bits in it. */
+ bits in it.
+
+ Note by passing in CONSTOP, we guarantee that the bits not set in
+ CONSTOP are not significant and will never be examined. We must
+ ensure that is the case by explicitly masking out those bits
+ before returning. */
varop = force_to_mode (varop, mode, constop, NULL_RTX, 0);
- /* If VAROP is a CLOBBER, we will fail so return it; if it is a
- CONST_INT, we are done. */
- if (GET_CODE (varop) == CLOBBER || GET_CODE (varop) == CONST_INT)
+ /* If VAROP is a CLOBBER, we will fail so return it. */
+ if (GET_CODE (varop) == CLOBBER)
return varop;
+ /* If VAROP is a CONST_INT, then we need to apply the mask in CONSTOP
+ to VAROP and return the new constant. */
+ if (GET_CODE (varop) == CONST_INT)
+ return GEN_INT (trunc_int_for_mode (INTVAL (varop) & constop, mode));
+
/* See what bits may be nonzero in VAROP. Unlike the general case of
a call to nonzero_bits, here we don't care about bits outside
MODE. */
--
GitLab