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| author | Jim Wilson <wilson@gcc.gnu.org> | 1993-05-26 15:39:50 -0700 |
|---|---|---|
| committer | Jim Wilson <wilson@gcc.gnu.org> | 1993-05-26 15:39:50 -0700 |
| commit | 2b7794ad0be64f46c4ad99ca580a5eabe86a3d37 (patch) | |
| tree | 2a67a2b99ed2ad51b71966af88d239703024c278 /gcc | |
| parent | 4055b808f5c0ba445811a205d3b67c24299df4e1 (diff) | |
| download | gcc-2b7794ad0be64f46c4ad99ca580a5eabe86a3d37.zip gcc-2b7794ad0be64f46c4ad99ca580a5eabe86a3d37.tar.gz gcc-2b7794ad0be64f46c4ad99ca580a5eabe86a3d37.tar.bz2 | |
(ashlsi3): Use shlo instead of shli.
From-SVN: r4577
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/i960/i960.md | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/gcc/config/i960/i960.md b/gcc/config/i960/i960.md index 191cee9..dd52829 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" |