From: Wilco Dijkstra <wdijkstr@arm.com>
Date: Wed, 4 Dec 2019 14:45:59 +0000 (+0000)
Subject: [AArch64] Add support for fused compare and branch
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=a4f3fa716f9fc6fbab40b5d247db60385c69cd90;p=gcc.git

[AArch64] Add support for fused compare and branch

Add support for fused compare with branch.  Rename the existing
AARCH64_FUSE_CMP_BRANCH to ALU_BRANCH, and AARCH64_FUSE_ALU_BRANCH
to ALU_CBZ to make it clear what is being fused.

    gcc/
	* config/aarch64/aarch64.c
	(thunderxt88_tunings): Use AARCH64_FUSE_ALU_BRANCH.
	(thunderx_tunings): Likewise.
	(tsv110_tunings): Use AARCH64_FUSE_ALU_BRANCH and AARCH64_FUSE_ALU_CBZ.
	(thunderx2t99_tunings): Likewise.
	(aarch_macro_fusion_pair_p): Add support for AARCH64_FUSE_CMP_BRANCH.
	* config/aarch64/aarch64-fusion-pairs.def: Add ALU_CBZ fusion.

From-SVN: r278966
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 29359ee3f5b..3d59aeab210 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2019-12-04  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	* config/aarch64/aarch64.c
+	(thunderxt88_tunings): Use AARCH64_FUSE_ALU_BRANCH.
+	(thunderx_tunings): Likewise.
+	(tsv110_tunings): Use AARCH64_FUSE_ALU_BRANCH and AARCH64_FUSE_ALU_CBZ.
+	(thunderx2t99_tunings): Likewise.
+	(aarch_macro_fusion_pair_p): Add support for AARCH64_FUSE_CMP_BRANCH.
+	* config/aarch64/aarch64-fusion-pairs.def: Add ALU_CBZ fusion.
+
 2019-12-04  Richard Biener  <rguenther@suse.de>
 
 	* tree-ssa-sccvn.c (vn_reference_lookup_3): Properly guard
diff --git a/gcc/config/aarch64/aarch64-fusion-pairs.def b/gcc/config/aarch64/aarch64-fusion-pairs.def
index ce4bb92d5c9..051009b42b2 100644
--- a/gcc/config/aarch64/aarch64-fusion-pairs.def
+++ b/gcc/config/aarch64/aarch64-fusion-pairs.def
@@ -35,5 +35,6 @@ AARCH64_FUSION_PAIR ("adrp+ldr", ADRP_LDR)
 AARCH64_FUSION_PAIR ("cmp+branch", CMP_BRANCH)
 AARCH64_FUSION_PAIR ("aes+aesmc", AES_AESMC)
 AARCH64_FUSION_PAIR ("alu+branch", ALU_BRANCH)
+AARCH64_FUSION_PAIR ("alu+cbz", ALU_CBZ)
 
 #undef AARCH64_FUSION_PAIR
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index c0d49fb7cf0..a3b18b381e1 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -915,7 +915,7 @@ static const struct tune_params thunderxt88_tunings =
   SVE_NOT_IMPLEMENTED, /* sve_width  */
   6, /* memmov_cost  */
   2, /* issue_rate  */
-  AARCH64_FUSE_CMP_BRANCH, /* fusible_ops  */
+  AARCH64_FUSE_ALU_BRANCH, /* fusible_ops  */
   "8",	/* function_align.  */
   "8",	/* jump_align.  */
   "8",	/* loop_align.  */
@@ -941,7 +941,7 @@ static const struct tune_params thunderx_tunings =
   SVE_NOT_IMPLEMENTED, /* sve_width  */
   6, /* memmov_cost  */
   2, /* issue_rate  */
-  AARCH64_FUSE_CMP_BRANCH, /* fusible_ops  */
+  AARCH64_FUSE_ALU_BRANCH, /* fusible_ops  */
   "8",	/* function_align.  */
   "8",	/* jump_align.  */
   "8",	/* loop_align.  */
@@ -968,8 +968,8 @@ static const struct tune_params tsv110_tunings =
   SVE_NOT_IMPLEMENTED, /* sve_width  */
   4,    /* memmov_cost  */
   4,    /* issue_rate  */
-  (AARCH64_FUSE_AES_AESMC | AARCH64_FUSE_CMP_BRANCH
-   | AARCH64_FUSE_ALU_BRANCH), /* fusible_ops  */
+  (AARCH64_FUSE_AES_AESMC | AARCH64_FUSE_ALU_BRANCH
+   | AARCH64_FUSE_ALU_CBZ), /* fusible_ops  */
   "16", /* function_align.  */
   "4",  /* jump_align.  */
   "8",  /* loop_align.  */
@@ -1103,8 +1103,8 @@ static const struct tune_params thunderx2t99_tunings =
   SVE_NOT_IMPLEMENTED, /* sve_width  */
   4, /* memmov_cost.  */
   4, /* issue_rate.  */
-  (AARCH64_FUSE_CMP_BRANCH | AARCH64_FUSE_AES_AESMC
-   | AARCH64_FUSE_ALU_BRANCH), /* fusible_ops  */
+  (AARCH64_FUSE_ALU_BRANCH | AARCH64_FUSE_AES_AESMC
+   | AARCH64_FUSE_ALU_CBZ), /* fusible_ops  */
   "16",	/* function_align.  */
   "8",	/* jump_align.  */
   "16",	/* loop_align.  */
@@ -20396,7 +20396,16 @@ aarch_macro_fusion_pair_p (rtx_insn *prev, rtx_insn *curr)
         }
     }
 
+  /* Fuse compare (CMP/CMN/TST/BICS) and conditional branch.  */
   if (aarch64_fusion_enabled_p (AARCH64_FUSE_CMP_BRANCH)
+      && prev_set && curr_set && any_condjump_p (curr)
+      && GET_CODE (SET_SRC (prev_set)) == COMPARE
+      && SCALAR_INT_MODE_P (GET_MODE (XEXP (SET_SRC (prev_set), 0)))
+      && reg_referenced_p (SET_DEST (prev_set), PATTERN (curr)))
+    return true;
+
+  /* Fuse flag-setting ALU instructions and conditional branch.  */
+  if (aarch64_fusion_enabled_p (AARCH64_FUSE_ALU_BRANCH)
       && any_condjump_p (curr))
     {
       unsigned int condreg1, condreg2;
@@ -20420,9 +20429,10 @@ aarch_macro_fusion_pair_p (rtx_insn *prev, rtx_insn *curr)
 	}
     }
 
+  /* Fuse ALU instructions and CBZ/CBNZ.  */
   if (prev_set
       && curr_set
-      && aarch64_fusion_enabled_p (AARCH64_FUSE_ALU_BRANCH)
+      && aarch64_fusion_enabled_p (AARCH64_FUSE_ALU_CBZ)
       && any_condjump_p (curr))
     {
       /* We're trying to match: