> -----Original Message----- > From: Richard Biener <rguent...@suse.de> > Sent: Thursday, July 7, 2022 8:47 AM > To: Tamar Christina <tamar.christ...@arm.com> > Cc: gcc-patches@gcc.gnu.org; nd <n...@arm.com> > Subject: RE: [PATCH]middle-end: don't lower past veclower [PR106063] > > On Thu, 7 Jul 2022, Tamar Christina wrote: > > > > -----Original Message----- > > > From: Richard Biener <rguent...@suse.de> > > > Sent: Thursday, July 7, 2022 8:19 AM > > > To: Tamar Christina <tamar.christ...@arm.com> > > > Cc: gcc-patches@gcc.gnu.org; nd <n...@arm.com> > > > Subject: Re: [PATCH]middle-end: don't lower past veclower [PR106063] > > > > > > On Tue, 5 Jul 2022, Tamar Christina wrote: > > > > > > > Hi All, > > > > > > > > My previous patch can cause a problem if the pattern matches after > > > > veclower as it may replace the construct with a vector sequence > > > > which the target may not directly support. > > > > > > > > As such don't perform the rewriting if after veclower. > > > > > > Note that when doing the rewriting before veclower to a variant not > > > supported by the target can cause veclower to generate absymal code. > > > In some cases we are very careful and try to at least preserve code > > > supported by the target over transforming that into a variant not > supported. > > > > > > That said, a better fix would be to check whether the target can > > > perform the new comparison. Before veclower it would be OK to do > > > the transform nevertheless in case it cannot do the original transform. > > > > This last statement is somewhat confusing. Did you want me to change > > it such that before veclower the rewrite is always done and after > > veclowering only if the target supports it? > > > > Or did you want me to never do the rewrite if the target doesn't support it? > > I meant before veclower you can do the rewrite if either the rewriting result > is supported by the target OR if the original expression is _not_ supported by > the target. The latter case might be not too important to worry doing (it > would still canonicalize for those targets then). After veclower you can only > rewrite under the former condition. >
Bootstrapped Regtested on aarch64-none-linux-gnu, x86_64-pc-linux-gnu
and no issues.
Ok for master? and backport to GCC 12?
Thanks,
Tamar
gcc/ChangeLog:
PR tree-optimization/106063
* match.pd: Only rewrite if target support it.
gcc/testsuite/ChangeLog:
PR tree-optimization/106063
* gcc.dg/pr106063.c: New test.
--- inline copy of patch ---
diff --git a/gcc/match.pd b/gcc/match.pd
index
40c09bedadb89dabb6622559a8f69df5384e61fd..5800a105c3cdada9d5e1d8019176ebbe5969ccb0
100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -6041,10 +6041,16 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(cmp (bit_and:c@2 @0 cst@1) integer_zerop)
(with { tree csts = bitmask_inv_cst_vector_p (@1); }
(if (csts && (VECTOR_TYPE_P (TREE_TYPE (@1)) || single_use (@2)))
- (if (TYPE_UNSIGNED (TREE_TYPE (@1)))
- (icmp @0 { csts; })
- (with { tree utype = unsigned_type_for (TREE_TYPE (@1)); }
- (icmp (view_convert:utype @0) { csts; }))))))))
+ (with { auto optab = VECTOR_TYPE_P (TREE_TYPE (@1))
+ ? optab_vector : optab_default;
+ tree utype = unsigned_type_for (TREE_TYPE (@1)); }
+ (if (target_supports_op_p (utype, icmp, optab)
+ || (optimize_vectors_before_lowering_p ()
+ && (!target_supports_op_p (type, cmp, optab)
+ || !target_supports_op_p (type, BIT_AND_EXPR, optab))))
+ (if (TYPE_UNSIGNED (TREE_TYPE (@1)))
+ (icmp @0 { csts; })
+ (icmp (view_convert:utype @0) { csts; })))))))))
/* When one argument is a constant, overflow detection can be simplified.
Currently restricted to single use so as not to interfere too much with
diff --git a/gcc/testsuite/gcc.dg/pr106063.c b/gcc/testsuite/gcc.dg/pr106063.c
new file mode 100644
index
0000000000000000000000000000000000000000..b23596724f6bb98c53af2dce77d31509bab10378
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr106063.c
@@ -0,0 +1,9 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-tree-forwprop --disable-tree-evrp" } */
+typedef __int128 __attribute__((__vector_size__ (16))) V;
+
+V
+foo (V v)
+{
+ return (v & (V){15}) == v;
+}
rb15911.patch
Description: rb15911.patch
