[AArch64][2/5] Improve aarch64_internal_mov_immediate by using faster algorithm

2015-09-20  Wilco Dijkstra  <wdijkstr@arm.com>

	* config/aarch64/aarch64.c (aarch64_internal_mov_immediate): Replace
	slow immediate matching loops with a faster algorithm.

From-SVN: r227947

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9810ec6e345745e43b3417853992e30c77ad90a7..a4504b0c19aebf5b8a293256275ee4015c8aa8fe 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2015-09-20  Wilco Dijkstra  <wdijkstr@arm.com>
+
+       * config/aarch64/aarch64.c (aarch64_internal_mov_immediate): Replace
+       slow immediate matching loops with a faster algorithm.
+
 2015-09-20  Wilco Dijkstra  <wdijkstr@arm.com>
 
        * config/aarch64/aarch64.c (aarch64_bitmask_imm): Reimplement using

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 2e7b9ec0567bbcfd1ae8f3cb424862f26949bdb8..8097c35041b2b5ef5a285b2e4a2147429999ef79 100644 (file)
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -1442,7 +1442,7 @@ aarch64_internal_mov_immediate (rtx dest, rtx imm, bool generate,
   unsigned HOST_WIDE_INT mask;
   int i;
   bool first;
-  unsigned HOST_WIDE_INT val;
+  unsigned HOST_WIDE_INT val, val2;
   bool subtargets;
   rtx subtarget;
   int one_match, zero_match, first_not_ffff_match;
@@ -1569,85 +1569,35 @@ aarch64_internal_mov_immediate (rtx dest, rtx imm, bool generate,
        }
     }
 
-  /* See if we can do it by arithmetically combining two
-     immediates.  */
-  for (i = 0; i < AARCH64_NUM_BITMASKS; i++)
+  if (zero_match != 2 && one_match != 2)
     {
-      int j;
-      mask = 0xffff;
+      /* Try emitting a bitmask immediate with a movk replacing 16 bits.
+        For a 64-bit bitmask try whether changing 16 bits to all ones or
+        zeroes creates a valid bitmask.  To check any repeated bitmask,
+        try using 16 bits from the other 32-bit half of val.  */
 
-      if (aarch64_uimm12_shift (val - aarch64_bitmasks[i])
-         || aarch64_uimm12_shift (-val + aarch64_bitmasks[i]))
+      for (i = 0; i < 64; i += 16, mask <<= 16)
        {
-         if (generate)
-           {
-             subtarget = subtargets ? gen_reg_rtx (DImode) : dest;
-             emit_insn (gen_rtx_SET (subtarget,
-                                     GEN_INT (aarch64_bitmasks[i])));
-             emit_insn (gen_adddi3 (dest, subtarget,
-                                    GEN_INT (val - aarch64_bitmasks[i])));
-           }
-         num_insns += 2;
-         return num_insns;
+         val2 = val & ~mask;
+         if (val2 != val && aarch64_bitmask_imm (val2, mode))
+           break;
+         val2 = val | mask;
+         if (val2 != val && aarch64_bitmask_imm (val2, mode))
+           break;
+         val2 = val2 & ~mask;
+         val2 = val2 | (((val2 >> 32) | (val2 << 32)) & mask);
+         if (val2 != val && aarch64_bitmask_imm (val2, mode))
+           break;
        }
-
-      for (j = 0; j < 64; j += 16, mask <<= 16)
+      if (i != 64)
        {
-         if ((aarch64_bitmasks[i] & ~mask) == (val & ~mask))
+         if (generate)
            {
-             if (generate)
-               {
-                 emit_insn (gen_rtx_SET (dest,
-                                         GEN_INT (aarch64_bitmasks[i])));
-                 emit_insn (gen_insv_immdi (dest, GEN_INT (j),
-                                            GEN_INT ((val >> j) & 0xffff)));
-               }
-             num_insns += 2;
-             return num_insns;
+             emit_insn (gen_rtx_SET (dest, GEN_INT (val2)));
+             emit_insn (gen_insv_immdi (dest, GEN_INT (i),
+                        GEN_INT ((val >> i) & 0xffff)));
            }
-       }
-    }
-
-  /* See if we can do it by logically combining two immediates.  */
-  for (i = 0; i < AARCH64_NUM_BITMASKS; i++)
-    {
-      if ((aarch64_bitmasks[i] & val) == aarch64_bitmasks[i])
-       {
-         int j;
-
-         for (j = i + 1; j < AARCH64_NUM_BITMASKS; j++)
-           if (val == (aarch64_bitmasks[i] | aarch64_bitmasks[j]))
-             {
-               if (generate)
-                 {
-                   subtarget = subtargets ? gen_reg_rtx (mode) : dest;
-                   emit_insn (gen_rtx_SET (subtarget,
-                                           GEN_INT (aarch64_bitmasks[i])));
-                   emit_insn (gen_iordi3 (dest, subtarget,
-                                          GEN_INT (aarch64_bitmasks[j])));
-                 }
-               num_insns += 2;
-               return num_insns;
-             }
-       }
-      else if ((val & aarch64_bitmasks[i]) == val)
-       {
-         int j;
-
-         for (j = i + 1; j < AARCH64_NUM_BITMASKS; j++)
-           if (val == (aarch64_bitmasks[j] & aarch64_bitmasks[i]))
-             {
-               if (generate)
-                 {
-                   subtarget = subtargets ? gen_reg_rtx (mode) : dest;
-                   emit_insn (gen_rtx_SET (subtarget,
-                                           GEN_INT (aarch64_bitmasks[j])));
-                   emit_insn (gen_anddi3 (dest, subtarget,
-                                          GEN_INT (aarch64_bitmasks[i])));
-                 }
-               num_insns += 2;
-               return num_insns;
-             }
+         return 2;
        }
     }