[PATCH] [MIPS] Prevent MSA branches from being put into delay slots

[Dragan Mladjenovic]

From: "Dragan Mladjenovic" <dmladjenovic@wavecomp.com>

 This patch tightens the instruction definitions to make sure
 that MSA branch instructions cannot be put into delay slots and have their
 delay slots eligible for being filled. Also, MSA *div*3 patterns use MSA
 branches for zero checks but are not marked as being multi instruction and
 thus could be put into delay slots. This patch fixes that.

 Testcase only covers if MSA branch delay slot is being filled.

gcc/ChangeLog:

2019-11-15  Zoran Jovanovic <zoran.jovanovic@mips.com>
		Dragan Mladjenovic  <dmladjenovic@wavecomp.com>

	* config/mips/mips-msa.md (msa_<msabr>_<msafmt_f>, msa_<msabr>_v_<msafmt_f>):
	Mark as not having "likely" version.
	* config/mips/mips.md (insn_count): The simd_div instruction with
	TARGET_CHECK_ZERO_DIV consists of 3 instructions.
	(can_delay): Exclude simd_branch.
	(defile_delay *): Add simd_branch instructions.
	They have one regular delay slot.

gcc/testsuite/ChangeLog:

2019-11-15  Dragan Mladjenovic  <dmladjenovic@wavecomp.com>

	* gcc.target/mips/msa-ds.c: New test.
---
 gcc/config/mips/mips-msa.md            |  6 ++++--
 gcc/config/mips/mips.md                | 10 ++++++++--
 gcc/testsuite/gcc.target/mips/msa-ds.c | 31 +++++++++++++++++++++++++++++++
 3 files changed, 43 insertions(+), 4 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/mips/msa-ds.c

diff --git a/gcc/config/mips/mips-msa.md b/gcc/config/mips/mips-msa.md
index 628423d..100cf99 100644
--- a/gcc/config/mips/mips-msa.md
+++ b/gcc/config/mips/mips-msa.md
@@ -2719,7 +2719,8 @@
 }
  [(set_attr "type" "simd_branch")
   (set_attr "mode" "<MODE>")
-  (set_attr "compact_form" "never")])
+  (set_attr "compact_form" "never")
+  (set_attr "branch_likely" "no")])
 
 (define_insn "msa_<msabr>_v_<msafmt_f>"
  [(set (pc) (if_then_else
@@ -2738,4 +2739,5 @@
 }
  [(set_attr "type" "simd_branch")
   (set_attr "mode" "TI")
-  (set_attr "compact_form" "never")])
+  (set_attr "compact_form" "never")
+  (set_attr "branch_likely" "no")])
diff --git a/gcc/config/mips/mips.md b/gcc/config/mips/mips.md
index 4de9731..929e368 100644
--- a/gcc/config/mips/mips.md
+++ b/gcc/config/mips/mips.md
@@ -560,6 +560,12 @@
 	 (eq_attr "type" "idiv,idiv3")
 	 (symbol_ref "mips_idiv_insns (GET_MODE (PATTERN (insn)))")
 
+	 ;; simd div have 3 instruction if TARGET_CHECK_ZERO_DIV is true.
+	 (eq_attr "type" "simd_div")
+	 (if_then_else (match_test "TARGET_CHECK_ZERO_DIV")
+		       (const_int 3)
+		       (const_int 1))
+
 	 (not (eq_attr "sync_mem" "none"))
 	 (symbol_ref "mips_sync_loop_insns (insn, operands)")]
 	(const_int 1)))
@@ -759,7 +765,7 @@
 
 ;; Can the instruction be put into a delay slot?
 (define_attr "can_delay" "no,yes"
-  (if_then_else (and (eq_attr "type" "!branch,call,jump")
+  (if_then_else (and (eq_attr "type" "!branch,call,jump,simd_branch")
 		     (eq_attr "hazard" "none")
 		     (match_test "get_attr_insn_count (insn) == 1"))
 		(const_string "yes")
@@ -1098,7 +1104,7 @@
 
 ;; Branches that have delay slots and don't have likely variants do
 ;; not annul on false.
-(define_delay (and (eq_attr "type" "branch")
+(define_delay (and (eq_attr "type" "branch,simd_branch")
 		   (not (match_test "TARGET_MIPS16"))
 		   (ior (match_test "TARGET_CB_NEVER")
 			(and (eq_attr "compact_form" "maybe")
diff --git a/gcc/testsuite/gcc.target/mips/msa-ds.c b/gcc/testsuite/gcc.target/mips/msa-ds.c
new file mode 100644
index 0000000..c6932b2
--- /dev/null
+++ b/gcc/testsuite/gcc.target/mips/msa-ds.c
@@ -0,0 +1,31 @@
+/* { dg-options "-mmsa -mfp64 -mhard-float" } */
+/* { dg-skip-if "code quality test" { *-*-* } { "-O0" } { "" } } */
+
+/* Check that delay slots for MSA branches are filled. */
+
+typedef unsigned v4si __attribute__ ((vector_size (16)));
+
+int __attribute__ ((cold)) foo (v4si v , int a, int b)
+{
+  int c = 0xf0f0f0f0;
+  int f = __builtin_msa_bnz_w (v);
+
+  if (f)
+   return a + c;
+  else
+   return b + c;
+}
+
+int __attribute__ ((cold)) bar (v4si v , int a, int b)
+{
+  int c = 0xf0f0f0f0;
+  int f = __builtin_msa_bz_w (v);
+
+  if (f)
+   return a + c;
+  else
+   return b + c;
+}
+
+/* { dg-final { scan-assembler-not "foo:.*nop.*jr.*foo," } } */
+/* { dg-final { scan-assembler-not "bar:.*nop.*jr.*bar," } } */
-- 
1.9.1