[gcc r14-8668] match: Fix vcond into conditional op folding [PR113607].

[gcc r14-8668] match: Fix vcond into conditional op folding [PR113607].

[Robin Dapp]

https://gcc.gnu.org/g:8123f3ca3fd891034a8366518e756f161c4ff40d

commit r14-8668-g8123f3ca3fd891034a8366518e756f161c4ff40d
Author: Robin Dapp <rdapp@ventanamicro.com>
Date:   Tue Jan 30 18:39:08 2024 +0100

    match: Fix vcond into conditional op folding [PR113607].
    
    In PR113607 we see an invalid fold of
    
      _429 = .COND_SHL (mask_patt_205.47_276, vect_cst__262, vect_cst__262, { 0, ... });
      vect_prephitmp_129.51_282 = _429;
      vect_iftmp.55_287 = VEC_COND_EXPR <mask_patt_209.54_286, vect_prephitmp_129.51_282, vect_cst__262>;
    
    to
    
      Applying pattern match.pd:9607, gimple-match-10.cc:3817
      gimple_simplified to vect_iftmp.55_287 = .COND_SHL (mask_patt_205.47_276, vect_cst__262, vect_cst__262, { 0, ... });
    
    where we essentially use COND_SHL's else instead of VEC_COND_EXPR's.
    
    This patch adjusts the corresponding match.pd pattern and makes it only
    match when the else values are the same.
    
    That, however, causes the exact test case for which this pattern was
    introduced for to fail.  Therefore XFAIL it for now.
    
    gcc/ChangeLog:
    
            PR middle-end/113607
    
            * match.pd: Make sure else values match when folding a
            vec_cond into a conditional operation.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.target/aarch64/sve/pre_cond_share_1.c: XFAIL.
            * gcc.target/riscv/rvv/autovec/pr113607-run.c: New test.
            * gcc.target/riscv/rvv/autovec/pr113607.c: New test.

Diff:
---
 gcc/match.pd                                       |  8 ++--
 .../gcc.target/aarch64/sve/pre_cond_share_1.c      |  2 +-
 .../gcc.target/riscv/rvv/autovec/pr113607-run.c    |  4 ++
 .../gcc.target/riscv/rvv/autovec/pr113607.c        | 49 ++++++++++++++++++++++
 4 files changed, 58 insertions(+), 5 deletions(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index a82bb08cd457..711c3a10c3ff 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -9592,18 +9592,18 @@ and,
 
 /* Detect simplification for vector condition folding where
 
-  c = mask1 ? (masked_op mask2 a b) : b
+  c = mask1 ? (masked_op mask2 a b els) : els
 
   into
 
-  c = masked_op (mask1 & mask2) a b
+  c = masked_op (mask1 & mask2) a b els
 
   where the operation can be partially applied to one operand. */
 
 (for cond_op (COND_BINARY)
  (simplify
   (vec_cond @0
-   (cond_op:s @1 @2 @3 @4) @3)
+   (cond_op:s @1 @2 @3 @4) @4)
   (cond_op (bit_and @1 @0) @2 @3 @4)))
 
 /* And same for ternary expressions.  */
@@ -9611,7 +9611,7 @@ and,
 (for cond_op (COND_TERNARY)
  (simplify
   (vec_cond @0
-   (cond_op:s @1 @2 @3 @4 @5) @4)
+   (cond_op:s @1 @2 @3 @4 @5) @5)
   (cond_op (bit_and @1 @0) @2 @3 @4 @5)))
 
 /* For pointers @0 and @2 and nonnegative constant offset @1, look for
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pre_cond_share_1.c b/gcc/testsuite/gcc.target/aarch64/sve/pre_cond_share_1.c
index b51d0f298ea1..e4f754d739c7 100644
--- a/gcc/testsuite/gcc.target/aarch64/sve/pre_cond_share_1.c
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pre_cond_share_1.c
@@ -129,4 +129,4 @@ fasten_main(size_t group, size_t ntypes, size_t nposes, size_t natlig, size_t na
 }
 
 /* { dg-final { scan-tree-dump-times {\.COND_MUL} 1 "optimized" } } */
-/* { dg-final { scan-tree-dump-times {\.VCOND} 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times {\.VCOND} 1 "optimized" { xfail *-*-* } } } */
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113607-run.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113607-run.c
new file mode 100644
index 000000000000..06074767ce5e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113607-run.c
@@ -0,0 +1,4 @@
+/* { dg-do run { target { riscv_v && rv64 } } } */
+/* { dg-options "-O3 -march=rv64gcv -mabi=lp64d -fdump-tree-optimized" } */
+
+#include "pr113607.c"
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113607.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113607.c
new file mode 100644
index 000000000000..70a936654972
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/pr113607.c
@@ -0,0 +1,49 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=rv64gcv -mabi=lp64d -fdump-tree-optimized" } */
+
+struct {
+  signed b;
+} c, d = {6};
+
+short e, f;
+int g[1000];
+signed char h;
+int i, j;
+long k, l;
+
+long m(long n, long o) {
+  if (n < 1 && o == 0)
+    return 0;
+  return n;
+}
+
+static int p() {
+  long q = 0;
+  int a = 0;
+  for (; e < 2; e += 1)
+    g[e * 7 + 1] = -1;
+  for (; h < 1; h += 1) {
+    k = g[8] || f;
+    l = m(g[f * 7 + 1], k);
+    a = l;
+    j = a < 0 || g[f * 7 + 1] < 0 || g[f * 7 + 1] >= 32 ? a : a << g[f * 7 + 1];
+    if (j)
+      ++q;
+  }
+  if (q)
+    c = d;
+  return i;
+}
+
+int main() {
+  p();
+  if (c.b != 6)
+    __builtin_abort ();
+}
+
+/* We must not fold VEC_COND_EXPR into COND_SHL.
+   Therefore, make sure that we still have 2/4 VCOND_MASKs with real else
+   value.  */
+
+/* { dg-final { scan-tree-dump-times { = \.VCOND_MASK.\([a-z0-9\._]+, [a-z0-9\._\{\}, ]+, [0-9\.\{\},]+\);} 0 "optimized" } } */
+/* { dg-final { scan-tree-dump-times { = \.VCOND_MASK.\([a-z0-9\._]+, [a-z0-9\._\{\}, ]+, [a-z0-9\._]+\);} 4 "optimized" } } */