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

[Jakub Jelinek]

On Sat, Jun 04, 2011 at 08:19:57AM -0700, H.J. Lu wrote:
> I don't think this pattern is correct.  See:
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49281

Fixed thusly, committed as obvious:

2011-06-04  Jakub Jelinek  <ja...@redhat.com>

        PR target/49281
        * config/i386/i386.md (*lea_general_4): Require INTVAL (operands[3])
        to be strictly smaller than 1 << shiftcount.

        * gcc.c-torture/execute/pr49281.c: New test.

--- gcc/config/i386/i386.md.jj  2011-06-01 10:20:02.000000000 +0200
+++ gcc/config/i386/i386.md     2011-06-04 17:21:02.000000000 +0200
@@ -6425,7 +6425,7 @@ (define_insn_and_split "*lea_general_4"
     || 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])))"
+       < ((unsigned HOST_WIDE_INT) 1 << INTVAL (operands[2])))"
   "#"
   "&& reload_completed"
   [(const_int 0)]
--- gcc/testsuite/gcc.c-torture/execute/pr49281.c.jj    2011-06-04 
17:29:39.000000000 +0200
+++ gcc/testsuite/gcc.c-torture/execute/pr49281.c       2011-06-04 
17:32:05.000000000 +0200
@@ -0,0 +1,25 @@
+/* PR target/49281 */
+
+extern void abort (void);
+
+__attribute__((noinline, noclone)) int
+foo (int x)
+{
+  return (x << 2) | 4;
+}
+
+__attribute__((noinline, noclone)) int
+bar (int x)
+{
+  return (x << 2) | 3;
+}
+
+int
+main ()
+{
+  if (foo (43) != 172 || foo (1) != 4 || foo (2) != 12)
+    abort ();
+  if (bar (43) != 175 || bar (1) != 7 || bar (2) != 11)
+    abort ();
+  return 0;
+}


        Jakub