aarch64: Tidy aarch64_split_compare_and_swap

With aarch64_track_speculation, we had extra code to do exactly what the
!strong_zero_p path already did.  The rest is reducing code duplication.

	* config/aarch64/aarch64 (aarch64_split_compare_and_swap): Disable
	strong_zero_p for aarch64_track_speculation; unify some code paths;
	use aarch64_gen_compare_reg instead of open-coding.

From-SVN: r275966

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index d8749b9b2e08a4192d671ebedd4bf0ad64253ad9..cef3a6e2b6de7a33e882a1a035f6fe61629dda35 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -16,6 +16,10 @@
        (aarch64_store_exclusive_pair): New.
        * config/aarch64/iterators.md (JUST_TI): New.
 
+       * config/aarch64/aarch64 (aarch64_split_compare_and_swap): Disable
+       strong_zero_p for aarch64_track_speculation; unify some code paths;
+       use aarch64_gen_compare_reg instead of open-coding.
+
 2019-09-19  Feng Xue  <fxue@os.amperecomputing.com>
 
        * ipa-fnsummary.c (set_cond_stmt_execution_predicate): Do not compute

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index a5c4f55627d0e1efec5dbc50fda2da15ea3f5e74..b937514e6f84f5a8af52bf277c9ce4f961d830de 100644 (file)
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -16955,13 +16955,11 @@ aarch64_emit_post_barrier (enum memmodel model)
 void
 aarch64_split_compare_and_swap (rtx operands[])
 {
-  rtx rval, mem, oldval, newval, scratch;
+  rtx rval, mem, oldval, newval, scratch, x, model_rtx;
   machine_mode mode;
   bool is_weak;
   rtx_code_label *label1, *label2;
-  rtx x, cond;
   enum memmodel model;
-  rtx model_rtx;
 
   rval = operands[0];
   mem = operands[1];
@@ -16982,7 +16980,8 @@ aarch64_split_compare_and_swap (rtx operands[])
        CBNZ    scratch, .label1
     .label2:
        CMP     rval, 0.  */
-  bool strong_zero_p = !is_weak && oldval == const0_rtx && mode != TImode;
+  bool strong_zero_p = (!is_weak && !aarch64_track_speculation &&
+                       oldval == const0_rtx && mode != TImode);
 
   label1 = NULL;
   if (!is_weak)
@@ -16995,35 +16994,20 @@ aarch64_split_compare_and_swap (rtx operands[])
   /* The initial load can be relaxed for a __sync operation since a final
      barrier will be emitted to stop code hoisting.  */
   if (is_mm_sync (model))
-    aarch64_emit_load_exclusive (mode, rval, mem,
-                                GEN_INT (MEMMODEL_RELAXED));
+    aarch64_emit_load_exclusive (mode, rval, mem, GEN_INT (MEMMODEL_RELAXED));
   else
     aarch64_emit_load_exclusive (mode, rval, mem, model_rtx);
 
   if (strong_zero_p)
-    {
-      if (aarch64_track_speculation)
-       {
-         /* Emit an explicit compare instruction, so that we can correctly
-            track the condition codes.  */
-         rtx cc_reg = aarch64_gen_compare_reg (NE, rval, const0_rtx);
-         x = gen_rtx_NE (GET_MODE (cc_reg), cc_reg, const0_rtx);
-       }
-      else
-       x = gen_rtx_NE (VOIDmode, rval, const0_rtx);
-
-      x = gen_rtx_IF_THEN_ELSE (VOIDmode, x,
-                               gen_rtx_LABEL_REF (Pmode, label2), pc_rtx);
-      aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x));
-    }
+    x = gen_rtx_NE (VOIDmode, rval, const0_rtx);
   else
     {
-      cond = aarch64_gen_compare_reg_maybe_ze (NE, rval, oldval, mode);
-      x = gen_rtx_NE (VOIDmode, cond, const0_rtx);
-      x = gen_rtx_IF_THEN_ELSE (VOIDmode, x,
-                               gen_rtx_LABEL_REF (Pmode, label2), pc_rtx);
-      aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x));
+      rtx cc_reg = aarch64_gen_compare_reg_maybe_ze (NE, rval, oldval, mode);
+      x = gen_rtx_NE (VOIDmode, cc_reg, const0_rtx);
     }
+  x = gen_rtx_IF_THEN_ELSE (VOIDmode, x,
+                           gen_rtx_LABEL_REF (Pmode, label2), pc_rtx);
+  aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x));
 
   aarch64_emit_store_exclusive (mode, scratch, mem, newval, model_rtx);
 
@@ -17044,22 +17028,16 @@ aarch64_split_compare_and_swap (rtx operands[])
       aarch64_emit_unlikely_jump (gen_rtx_SET (pc_rtx, x));
     }
   else
-    {
-      cond = gen_rtx_REG (CCmode, CC_REGNUM);
-      x = gen_rtx_COMPARE (CCmode, scratch, const0_rtx);
-      emit_insn (gen_rtx_SET (cond, x));
-    }
+    aarch64_gen_compare_reg (NE, scratch, const0_rtx);
 
   emit_label (label2);
+
   /* If we used a CBNZ in the exchange loop emit an explicit compare with RVAL
      to set the condition flags.  If this is not used it will be removed by
      later passes.  */
   if (strong_zero_p)
-    {
-      cond = gen_rtx_REG (CCmode, CC_REGNUM);
-      x = gen_rtx_COMPARE (CCmode, rval, const0_rtx);
-      emit_insn (gen_rtx_SET (cond, x));
-    }
+    aarch64_gen_compare_reg (NE, rval, const0_rtx);
+
   /* Emit any final barrier needed for a __sync operation.  */
   if (is_mm_sync (model))
     aarch64_emit_post_barrier (model);