[pushed] i386: Split MOVBE alternatives out of *bswaphi2_movbe to drop flags clobber
Uros Bizjak <[email protected]>
| Newsgroups | gmane.comp.gcc.patches |
|---|---|
| Message-ID | <CAFULd4Zgg6rc7Ky-xKt3xdzAJ+cDvLPeXFLaE-SnFj9EdO=dqQ@mail.gmail.com> |
The MOVBE alternatives in *bswaphi2_movbe carry a (clobber (reg:CC FLAGS_REG)) that only the ROL alternative sharing the pattern actually needs. MOVBE does not touch EFLAGS, so once reload has picked an alternative, split the MOVBE cases out into a new clobber-free *movbehi2 pattern. gcc/ChangeLog: * config/i386/i386.md (*movbehi2): New insn, split from the movbe alternatives of *bswaphi2_movbe. (*bswaphi2_movbe): Convert to define_insn_and_split. Split the MOVBE alternatives (mem<->reg) post-reload into *movbehi2 to drop the now-unneeded flags clobber. Bootstrapped and regression tested on x86_64-pc-linux-gnu. Uros.
p.diff.txt
(text/plain, 1.4 KB)
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 3b0f8b2cccd..73d005ef5ed 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -23658,7 +23658,21 @@ (define_expand "bswaphi2"
operands[1] = force_reg (HImode, operands[1]);
})
-(define_insn "*bswaphi2_movbe"
+(define_insn "*movbehi2"
+ [(set (match_operand:HI 0 "nonimmediate_operand" "=r,m")
+ (bswap:HI (match_operand:HI 1 "nonimmediate_operand" "m,r")))]
+ "TARGET_MOVBE
+ && MEM_P (operands[0]) != MEM_P (operands[1])
+ && reload_completed"
+ "movbe{w}\t{%1, %0|%0, %1}"
+ [(set_attr "type" "imov")
+ (set_attr "modrm" "1")
+ (set_attr "prefix_0f" "1")
+ (set_attr "prefix_extra" "1")
+ (set_attr "mode" "HI")])
+
+;; Convert movbe to avoid flags dependency.
+(define_insn_and_split "*bswaphi2_movbe"
[(set (match_operand:HI 0 "nonimmediate_operand" "=Q,r,r,m")
(bswap:HI (match_operand:HI 1 "nonimmediate_operand" "0,0,m,r")))
(clobber (reg:CC FLAGS_REG))]
@@ -23667,8 +23681,13 @@ (define_insn "*bswaphi2_movbe"
"@
xchg{b}\t{%h0, %b0|%b0, %h0}
rol{w}\t{$8, %0|%0, 8}
- movbe{w}\t{%1, %0|%0, %1}
- movbe{w}\t{%1, %0|%0, %1}"
+ #
+ #"
+ "&& MEM_P (operands[0]) != MEM_P (operands[1])
+ && reload_completed"
+ [(set (match_dup 0)
+ (bswap:HI (match_dup 1)))]
+ ""
[(set_attr "type" "imov,rotate1,imov,imov")
(set_attr "modrm" "*,*,1,1")
(set_attr "prefix_0f" "*,*,1,1")