[gcc r11-7656] match.pd: Don't optimize vector X + (X << C) -> X * (1 + (1 << C)) if there is no mult support [PR99

[gcc r11-7656] match.pd: Don't optimize vector X + (X << C) -> X * (1 + (1 << C)) if there is no mult support [PR99

[Jakub Jelinek]

https://gcc.gnu.org/g:bbdf59fdbc2ce41ccfac807b15cf3fac7b465a56

commit r11-7656-gbbdf59fdbc2ce41ccfac807b15cf3fac7b465a56
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sat Mar 13 08:56:15 2021 +0100

    match.pd: Don't optimize vector X + (X << C) -> X * (1 + (1 << C)) if there is no mult support [PR99544]
    
    E.g. on aarch64, the target has V2DImode addition and shift by scalar
    optabs, but doesn't have V2DImode multiply.  The following testcase
    ICEs because this simplification is done after last lowering, but
    generally, even if it is done before that, turning it into a multiplication
    will not be an improvement because that means scalarization, while the former
    can be done in vectors.
    
    It would be nice if we added expansion support for vector multiplication
    by uniform constants using shifts and additions like we have for scalar
    multiplication, but that is something that can be done in stage1.
    
    2021-03-13  Jakub Jelinek  <jakub@redhat.com>
    
            PR tree-optimization/99544
            * match.pd (X + (X << C) -> X * (1 + (1 << C))): Don't simplify
            if for vector types multiplication can't be done in type's mode.
    
            * gcc.dg/gomp/pr99544.c: New test.

Diff:
---
 gcc/match.pd                        | 10 ++++++++--
 gcc/testsuite/gcc.dg/gomp/pr99544.c | 13 +++++++++++++
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index a34c283e28c..036f92fa959 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -2788,7 +2788,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (plus:c @0 (lshift:s @0 INTEGER_CST@1))
   (if (ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
        && tree_fits_uhwi_p (@1)
-       && tree_to_uhwi (@1) < element_precision (type))
+       && tree_to_uhwi (@1) < element_precision (type)
+       && (INTEGRAL_TYPE_P (TREE_TYPE (@0))
+	   || optab_handler (smul_optab,
+			     TYPE_MODE (type)) != CODE_FOR_nothing))
    (with { tree t = type;
 	   if (!TYPE_OVERFLOW_WRAPS (t)) t = unsigned_type_for (t);
 	   wide_int w = wi::set_bit_in_zero (tree_to_uhwi (@1),
@@ -2804,7 +2807,10 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
        && tree_fits_uhwi_p (@1)
        && tree_to_uhwi (@1) < element_precision (type)
        && tree_fits_uhwi_p (@2)
-       && tree_to_uhwi (@2) < element_precision (type))
+       && tree_to_uhwi (@2) < element_precision (type)
+       && (INTEGRAL_TYPE_P (TREE_TYPE (@0))
+	   || optab_handler (smul_optab,
+			     TYPE_MODE (type)) != CODE_FOR_nothing))
    (with { tree t = type;
 	   if (!TYPE_OVERFLOW_WRAPS (t)) t = unsigned_type_for (t);
 	   unsigned int prec = element_precision (type);
diff --git a/gcc/testsuite/gcc.dg/gomp/pr99544.c b/gcc/testsuite/gcc.dg/gomp/pr99544.c
new file mode 100644
index 00000000000..4ea07cf2b4d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/gomp/pr99544.c
@@ -0,0 +1,13 @@
+/* PR tree-optimization/99544 */
+/* { dg-do compile } */
+/* { dg-options "-Os -fopenmp" } */
+
+long
+foo (long a, long b, long c)
+{
+  long d, e;
+  #pragma omp teams distribute parallel for simd firstprivate (a, b, c) lastprivate(e)
+  for (d = a; d < b; d++)
+    e = c + d * 5;
+  return e;
+}