[gcc/devel/c++-modules] [PATCH PR96357][GCC][AArch64]: could not split insn UNSPEC_COND_FSUB with AArch64 SVE

[gcc/devel/c++-modules] [PATCH PR96357][GCC][AArch64]: could not split insn UNSPEC_COND_FSUB with AArch64 SVE

[Nathan Sidwell]

https://gcc.gnu.org/g:b648814c02eb418aaf27897c480452172ee96303

commit b648814c02eb418aaf27897c480452172ee96303
Author: Przemyslaw Wirkus <przemyslaw.wirkus@arm.com>
Date:   Fri Aug 28 11:31:04 2020 +0100

    [PATCH PR96357][GCC][AArch64]: could not split insn UNSPEC_COND_FSUB with AArch64 SVE
    
    Problem is related to that operand 4 (In original pattern
    cond_sub<mode>_any_const) is no longer the same as operand 1, and so
    the pattern doesn't match the split condition.
    
    Pattern cond_sub<mode>_any_const is being split by this patch into two
    separate patterns:
    * Pattern cond_sub<mode>_relaxed_const now matches const_int
      SVE_RELAXED_GP operand.
    * Pattern cond_sub<mode>_strict_const now matches const_int
      SVE_STRICT_GP operand.
    * Remove aarch64_sve_pred_dominates_p condition from both patterns.
    
    gcc/ChangeLog:
    
            PR target/96357
            * config/aarch64/aarch64-sve.md
            (cond_sub<mode>_relaxed_const): Updated and renamed from
            cond_sub<mode>_any_const pattern.
            (cond_sub<mode>_strict_const): New pattern.
    
    gcc/testsuite/ChangeLog:
    
            PR target/96357
            * gcc.target/aarch64/sve/pr96357.c: New test.

Diff:
---
 gcc/config/aarch64/aarch64-sve.md              | 42 +++++++++++++++++++++++---
 gcc/testsuite/gcc.target/aarch64/sve/pr96357.c | 25 +++++++++++++++
 2 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/gcc/config/aarch64/aarch64-sve.md b/gcc/config/aarch64/aarch64-sve.md
index 182813c1c5c..cd79aba90ec 100644
--- a/gcc/config/aarch64/aarch64-sve.md
+++ b/gcc/config/aarch64/aarch64-sve.md
@@ -5234,21 +5234,22 @@
 
 ;; Predicated floating-point subtraction from a constant, merging with an
 ;; independent value.
-(define_insn_and_rewrite "*cond_sub<mode>_any_const"
+;;
+;; The subtraction predicate and the merge predicate are allowed to be
+;; different.
+(define_insn_and_rewrite "*cond_sub<mode>_relaxed_const"
   [(set (match_operand:SVE_FULL_F 0 "register_operand" "=w, w, ?w")
 	(unspec:SVE_FULL_F
 	  [(match_operand:<VPRED> 1 "register_operand" "Upl, Upl, Upl")
 	   (unspec:SVE_FULL_F
 	     [(match_operand 5)
-	      (match_operand:SI 6 "aarch64_sve_gp_strictness")
+	      (const_int SVE_RELAXED_GP)
 	      (match_operand:SVE_FULL_F 2 "aarch64_sve_float_arith_immediate")
 	      (match_operand:SVE_FULL_F 3 "register_operand" "w, w, w")]
 	     UNSPEC_COND_FSUB)
 	   (match_operand:SVE_FULL_F 4 "aarch64_simd_reg_or_zero" "Dz, 0, w")]
 	  UNSPEC_SEL))]
-  "TARGET_SVE
-   && !rtx_equal_p (operands[3], operands[4])
-   && aarch64_sve_pred_dominates_p (&operands[5], operands[1])"
+  "TARGET_SVE && !rtx_equal_p (operands[3], operands[4])"
   "@
    movprfx\t%0.<Vetype>, %1/z, %3.<Vetype>\;fsubr\t%0.<Vetype>, %1/m, %0.<Vetype>, #%2
    movprfx\t%0.<Vetype>, %1/m, %3.<Vetype>\;fsubr\t%0.<Vetype>, %1/m, %0.<Vetype>, #%2
@@ -5271,6 +5272,37 @@
   [(set_attr "movprfx" "yes")]
 )
 
+;; Predicated floating-point subtraction from a constant, merging with an
+;; independent value.
+;;
+;; The subtraction predicate and the merge predicate must be the same.
+(define_insn_and_rewrite "*cond_sub<mode>_strict_const"
+  [(set (match_operand:SVE_FULL_F 0 "register_operand" "=w, w, ?w")
+	(unspec:SVE_FULL_F
+	  [(match_operand:<VPRED> 1 "register_operand" "Upl, Upl, Upl")
+	   (unspec:SVE_FULL_F
+	     [(match_dup 1)
+	      (const_int SVE_STRICT_GP)
+	      (match_operand:SVE_FULL_F 2 "aarch64_sve_float_arith_immediate")
+	      (match_operand:SVE_FULL_F 3 "register_operand" "w, w, w")]
+	     UNSPEC_COND_FSUB)
+	   (match_operand:SVE_FULL_F 4 "aarch64_simd_reg_or_zero" "Dz, 0, w")]
+	  UNSPEC_SEL))]
+  "TARGET_SVE && !rtx_equal_p (operands[3], operands[4])"
+  "@
+   movprfx\t%0.<Vetype>, %1/z, %3.<Vetype>\;fsubr\t%0.<Vetype>, %1/m, %0.<Vetype>, #%2
+   movprfx\t%0.<Vetype>, %1/m, %3.<Vetype>\;fsubr\t%0.<Vetype>, %1/m, %0.<Vetype>, #%2
+   #"
+  "&& reload_completed
+   && register_operand (operands[4], <MODE>mode)
+   && !rtx_equal_p (operands[0], operands[4])"
+  {
+    emit_insn (gen_vcond_mask_<mode><vpred> (operands[0], operands[3],
+                                             operands[4], operands[1]));
+    operands[4] = operands[3] = operands[0];
+  }
+  [(set_attr "movprfx" "yes")]
+)
 ;; Register merging forms are handled through SVE_COND_FP_BINARY.
 
 ;; -------------------------------------------------------------------------
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pr96357.c b/gcc/testsuite/gcc.target/aarch64/sve/pr96357.c
new file mode 100644
index 00000000000..e52867f5729
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pr96357.c
@@ -0,0 +1,25 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=armv8.2-a+sve" } */
+
+int d;
+
+void
+f1(char f, char *g, char *h, char *l, char *n) {
+  double i = d, j = 1.0 - f, k = j ? d : j;
+  if (k == 1.0)
+    i = 0.0;
+  *l = *n = *g = *h = i * 0.5;
+}
+
+void
+f2() {
+  int a, m, c;
+  for (c = 2048; c; c--) {
+    char b = a++;
+    f1(b, m, m + 1, m + 2, m + 3); /*{ dg-warning {passing argument [0-9]+ of 'f1' makes pointer from integer without a cast} } */
+    m += 4;
+  }
+}
+
+/* { dg-final { scan-assembler {\tmovprfx\tz[0-9]+, z[0-9]+} } } */
+/* { dg-final { scan-assembler {\tfsubr\tz[0-9]+\.d, p[0-7]/m, z[0-9]+\.d, #1.0} } } */