PATCH: PR target/59379: [4.9 Regression] gomp_init_num_threads is compiled into an infinite loop with --with-arch=corei7 --with-cpu=slm

[H.J. Lu]

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)))

we don't need to do it twice.  This patch implements above. Tested
on Linux/x86-64 without regressions.  OK for trunk and release
branches?

Thanks.

H.J.
---
2014-01-18  H.J. Lu  <hongjiu...@intel.com>

        PR target/59379
        * config/i386/i386.c (ix86_split_lea_for_addr): Properly
        zero-extends SImode to DImode.

diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c
index ff210c8..346b0cb 100644
--- a/gcc/config/i386/i386.c
+++ b/gcc/config/i386/i386.c
@@ -18342,6 +18342,23 @@ ix86_split_lea_for_addr (rtx insn, rtx operands[], 
enum machine_mode mode)
     }
   else
     {
+      if (mode != GET_MODE (operands[0]))
+       {
+         gcc_assert (mode == SImode && GET_MODE (operands[0]) == DImode);
+         if ((!parts.disp || parts.disp == const0_rtx)
+             && ((parts.base && !parts.index)
+                 || (!parts.base && parts.index)))
+           {
+             if (parts.base)
+               emit_insn (gen_zero_extendsidi2 (operands[0],
+                                                parts.base));
+             else
+               emit_insn (gen_zero_extendsidi2 (operands[0],
+                                                parts.index));
+             return;
+           }
+       }
+
       if (!parts.base)
        {
          if (regno0 != regno2)
@@ -18375,7 +18392,7 @@ ix86_split_lea_for_addr (rtx insn, rtx operands[], enum 
machine_mode mode)
                ix86_emit_binop (PLUS, mode, target, parts.disp);
 
              ix86_emit_binop (PLUS, mode, target, tmp1);
-             return;
+             goto check_mode;
            }
 
          ix86_emit_binop (PLUS, mode, target, tmp);
@@ -18384,6 +18401,13 @@ ix86_split_lea_for_addr (rtx insn, rtx operands[], 
enum machine_mode mode)
       if (parts.disp && parts.disp != const0_rtx)
        ix86_emit_binop (PLUS, mode, target, parts.disp);
     }
+
+check_mode:
+  if (mode != GET_MODE (operands[0]))
+    {
+      gcc_assert (mode == SImode && GET_MODE (operands[0]) == DImode);
+      emit_insn (gen_zero_extendsidi2 (operands[0], target));
+    }
 }
 
 /* Return true if it is ok to optimize an ADD operation to LEA