[PATCH][PR tree-optimization/122478] match.pd: fix simplify pattern for view_convert...

The pattern introduced in r16-4682-g5eafa8d16be873 couldn't handle
conversion from <unnamed-unsigned:1> to unsigned char, which ended up
causing a gimple checking failure reported in PR122478.  This patch fixes
the pattern by prohibiting widening integral conversions in addition to
the narrowing ones, or equivalently, requiring that the converted-to and
converted-from types of the VCE both have precision equal to their size.
Since type_has_mode_precision_p () does not apply to vector types, filter
them out by adding a !INTEGRAL_TYPE_P () check on TREE_TYPE (@0).

Bootstrapped and regtested on aarch64 and x86_64, regtested on i386 and
riscv64, one GIMPLE test added.

	PR tree-optimization/122478

gcc/ChangeLog:

	* match.pd: Fix the view_convert (BIT_FIELD_REF) pattern.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/pr122478.c: New test.

diff --git a/gcc/match.pd b/gcc/match.pd
index 00493d6ad993ed3276f120a14c043a5e3ae0a493..b65adece8dc666cee9625489602ea7a64f4308e3 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -5658,10 +5658,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
 
 /* Squash view_converts of BFRs if no precision is lost.  */
 (simplify
-  (view_convert (BIT_FIELD_REF @1 @2 @3))
+  (view_convert (BIT_FIELD_REF@0 @1 @2 @3))
   (if (is_gimple_reg_type (type)
        && (!INTEGRAL_TYPE_P (type)
-          || type_has_mode_precision_p (type)))
+          || !INTEGRAL_TYPE_P (TREE_TYPE (@0))
+          || (type_has_mode_precision_p (type)
+              && type_has_mode_precision_p (TREE_TYPE (@0)))))
    (BIT_FIELD_REF:type @1 @2 @3)))
 
 /* For integral conversions with the same precision or pointer

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr122478.c b/gcc/testsuite/gcc.dg/tree-ssa/pr122478.c
new file mode 100644 (file)
index 0000000..bc63f71
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr122478.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-additional-options "-fgimple" } */
+
+unsigned char __GIMPLE (ssa)
+foo (unsigned short mask__701)
+{
+  _Bool _19;
+  unsigned char _180;
+
+__BB(2):
+  _19 = __BIT_FIELD_REF <_Bool> (mask__701, 1, 12);
+  _180 = __VIEW_CONVERT<unsigned char>(_19);
+  return _180;
+}
+
+/* { dg-final { scan-tree-dump-times "VIEW_CONVERT_EXPR" "optimized" 1 } } */