On Sat, Jan 18, 2014 at 9:15 PM, H.J. Lu <hjl.to...@gmail.com> wrote:
> For LEA operation with SImode_address_operand, which zero-extends SImode
> to DImode, ix86_split_lea_for_addr turns
>
> (set (reg:DI) ...)
>
> into
>
> (set (reg:SI) ...)
>
> We need to do
>
> (set (reg:DI) (zero_extend:DI (reg:SI)))
>
> at the end. If the LEA operation is
>
> (set (reg:DI) (zero_extend:DI (reg:SI)))
ree pass should remove these. However, we can just emit zero-extend
insn at the end of sequence, and ree (which is located after
post-reload split) should handle it:
--cut here--
Index: config/i386/i386.md
===================================================================
--- config/i386/i386.md (revision 206753)
+++ config/i386/i386.md (working copy)
@@ -5428,12 +5428,17 @@
operands[0] = SET_DEST (pat);
operands[1] = SET_SRC (pat);
- /* Emit all operations in SImode for zero-extended addresses. Recall
- that x86_64 inheretly zero-extends SImode operations to DImode. */
+ /* Emit all operations in SImode for zero-extended addresses. */
if (SImode_address_operand (operands[1], VOIDmode))
mode = SImode;
ix86_split_lea_for_addr (curr_insn, operands, mode);
+
+ /* Zero-extend return register to DImode for zero-extended addresses. */
+ if (mode != <MODE>mode)
+ emit_insn (gen_zero_extendsidi2
+ (operands[0], gen_lowpart ((mode), operands[0])));
+
DONE;
}
[(set_attr "type" "lea")
--cut here--
The patch was tested with a testcase from Comment #9 of the PR using
"-O --march=corei7 -mtune=slm", and resulting binary runs without
problems.
Uros.
