From: Jim Wilson <wilson@gcc.gnu.org>
Date: Wed, 26 May 1993 22:39:50 +0000 (-0700)
Subject: (ashlsi3): Use shlo instead of shli.
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=2b7794ad0be64f46c4ad99ca580a5eabe86a3d37;p=gcc.git

(ashlsi3): Use shlo instead of shli.

From-SVN: r4577
---

diff --git a/gcc/config/i960/i960.md b/gcc/config/i960/i960.md
index 191cee99032..dd528291043 100644
--- a/gcc/config/i960/i960.md
+++ b/gcc/config/i960/i960.md
@@ -2092,12 +2092,20 @@
 
 ;; Arithmetic shift instructions.
 
+;; The shli instruction generates an overflow fault if the sign changes.
+;; In the case of overflow, it does not give the natural result, it instead
+;; gives the last shift value before the overflow.  We can not use this
+;; instruction because gcc thinks that arithmetic left shift and logical
+;; left shift are identical, and sometimes canonicalizes the logical left
+;; shift to an arithmetic left shift.  Therefore we must always use the
+;; logical left shift instruction.
+
 (define_insn "ashlsi3"
   [(set (match_operand:SI 0 "register_operand" "=d")
 	(ashift:SI (match_operand:SI 1 "arith_operand" "dI")
 		   (match_operand:SI 2 "arith_operand" "dI")))]
   ""
-  "shli	%2,%1,%0"
+  "shlo	%2,%1,%0"
   [(set_attr "type" "alu2")])
 
 (define_insn "ashrsi3"