LRA: Implement commutative operands exchange for combining secondary memory reload...

The patch implements trying commutative operands exchange for
combining secondary memory reload and original insn.

        PR rtl-optimization/109052

gcc/ChangeLog:

	* lra-constraints.cc: (combine_reload_insn): New function.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr109052-2.c: New.

diff --git a/gcc/lra-constraints.cc b/gcc/lra-constraints.cc
index 405b8b9..ff4e8f0 100644 (file)
--- a/gcc/lra-constraints.cc
+++ b/gcc/lra-constraints.cc
@@ -5061,7 +5061,23 @@ combine_reload_insn (rtx_insn *from, rtx_insn *to)
       curr_insn = to;
       curr_id = lra_get_insn_recog_data (curr_insn);
       curr_static_id = curr_id->insn_static_data;
-      ok_p = !curr_insn_transform (true);
+      for (bool swapped_p = false;;)
+       {
+         ok_p = !curr_insn_transform (true);
+         if (ok_p || curr_static_id->commutative < 0)
+           break;
+         swap_operands (curr_static_id->commutative);
+         if (lra_dump_file != NULL)
+           {
+             fprintf (lra_dump_file,
+                      "    Swapping %scombined insn operands:\n",
+                      swapped_p ? "back " : "");
+             dump_insn_slim (lra_dump_file, to);
+           }
+         if (swapped_p)
+           break;
+         swapped_p = true;
+       }
       curr_insn = saved_insn;
       curr_id = lra_get_insn_recog_data (curr_insn);
       curr_static_id = curr_id->insn_static_data;

diff --git a/gcc/testsuite/gcc.target/i386/pr109052-2.c b/gcc/testsuite/gcc.target/i386/pr109052-2.c
new file mode 100644 (file)
index 0000000..337d1f4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr109052-2.c
@@ -0,0 +1,10 @@
+/* { dg-do compile { target { ! ia32 } } } */
+/* { dg-options "-O2 -mfpmath=both -mavx -fno-math-errno" } */
+
+double foo (double a, double b)
+{
+  double z = __builtin_fmod (a, 3.14);
+  return z * b;
+}
+
+/* { dg-final { scan-assembler-not "vmulsd\[ \t]\+%xmm\[0-9]\+, %xmm\[0-9]\+, %xmm\[0-9]\+"} } */