[PATCH] Optimize (x * 8) | 5 and (x << 3) ^ 3 to use lea (PR target/48688)

[Jakub Jelinek <jakub@redhat.com>]

Hi!

This splitter allows us to optimize (x {* {2,4,8},<< {1,2,3}}) {|,^} y
for constant integer y <= {1ULL,3ULL,7ULL} using lea{l,q} (| or ^ in
that case, when the low bits are known to be all 0, is like plus).

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2011-04-20  Jakub Jelinek  <jakub@redhat.com>

	PR target/48688
	* config/i386/i386.md (*lea_general_4): New define_insn_and_split.

	* gcc.target/i386/pr48688.c: New test.

--- gcc/config/i386/i386.md.jj	2011-04-19 14:08:55.000000000 +0200
+++ gcc/config/i386/i386.md	2011-04-20 14:34:50.000000000 +0200
@@ -6646,6 +6646,40 @@ (define_insn_and_split "*lea_general_3_z
 }
   [(set_attr "type" "lea")
    (set_attr "mode" "SI")])
+
+(define_insn_and_split "*lea_general_4"
+  [(set (match_operand:SWI 0 "register_operand" "=r")
+	(any_or:SWI (ashift:SWI (match_operand:SWI 1 "index_register_operand" "l")
+				(match_operand:SWI 2 "const_int_operand" "n"))
+		    (match_operand 3 "const_int_operand" "n")))]
+  "(<MODE>mode == DImode
+    || <MODE>mode == SImode
+    || !TARGET_PARTIAL_REG_STALL
+    || optimize_function_for_size_p (cfun))
+   && ((unsigned HOST_WIDE_INT) INTVAL (operands[2])) - 1 < 3
+   && ((unsigned HOST_WIDE_INT) INTVAL (operands[3])
+       <= ((unsigned HOST_WIDE_INT) 1 << INTVAL (operands[2])))"
+  "#"
+  "&& reload_completed"
+  [(const_int 0)]
+{
+  rtx pat;
+  if (<MODE>mode != DImode)
+    operands[0] = gen_lowpart (SImode, operands[0]);
+  operands[1] = gen_lowpart (Pmode, operands[1]);
+  operands[2] = GEN_INT (1 << INTVAL (operands[2]));
+  pat = plus_constant (gen_rtx_MULT (Pmode, operands[1], operands[2]),
+		       INTVAL (operands[3]));
+  if (Pmode != SImode && <MODE>mode != DImode)
+    pat = gen_rtx_SUBREG (SImode, pat, 0);
+  emit_insn (gen_rtx_SET (VOIDmode, operands[0], pat));
+  DONE;
+}
+  [(set_attr "type" "lea")
+   (set (attr "mode")
+      (if_then_else (eq (symbol_ref "<MODE>mode == DImode") (const_int 0))
+	(const_string "SI")
+	(const_string "DI")))])
 \f
 ;; Subtract instructions
 
--- gcc/testsuite/gcc.target/i386/pr48688.c.jj	2011-04-20 14:55:37.000000000 +0200
+++ gcc/testsuite/gcc.target/i386/pr48688.c	2011-04-20 14:57:03.000000000 +0200
@@ -0,0 +1,24 @@
+/* PR target/48688 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int fn1 (int x) { return (x << 3) | 5; }
+int fn2 (int x) { return (x * 8) | 5; }
+int fn3 (int x) { return (x << 3) + 5; }
+int fn4 (int x) { return (x * 8) + 5; }
+int fn5 (int x) { return (x << 3) ^ 5; }
+int fn6 (int x) { return (x * 8) ^ 5; }
+long fn7 (long x) { return (x << 3) | 5; }
+long fn8 (long x) { return (x * 8) | 5; }
+long fn9 (long x) { return (x << 3) + 5; }
+long fn10 (long x) { return (x * 8) + 5; }
+long fn11 (long x) { return (x << 3) ^ 5; }
+long fn12 (long x) { return (x * 8) ^ 5; }
+long fn13 (unsigned x) { return (x << 3) | 5; }
+long fn14 (unsigned x) { return (x * 8) | 5; }
+long fn15 (unsigned x) { return (x << 3) + 5; }
+long fn16 (unsigned x) { return (x * 8) + 5; }
+long fn17 (unsigned x) { return (x << 3) ^ 5; }
+long fn18 (unsigned x) { return (x * 8) ^ 5; }
+
+/* { dg-final { scan-assembler-not "\[ \t\]x?or\[bwlq\]\[ \t\]" } } */

	Jakub