There are 2 patterns that are similar in match.pd for changing into
a smaller abs. One handles `abs((ext)a)` and one for `(trunc)abs((ext)a)`.
The one with the truncate afterwards does not use absu for integer types
which can introduce undefined behavior in some cases.
So let's restrict the second one to non integral types as the first one
will handle those always; the check for casting from unsigned is another
difference but the casting from unsigned is handled by a different abs
pattern for non-negative values.
Bootstrapped and tested on x86_64-linux-gnu.
PR tree-optimization/127689
gcc/ChangeLog:
* match.pd (`(trunc)abs((ext)a)`): Move right
after `abs((ext)a)` pattern. Restrict to
non integral types.
gcc/testsuite/ChangeLog:
* gcc.dg/torture/pr127689-1.c: New test.
Signed-off-by: Andrea Pinski <[email protected]>
---
gcc/match.pd | 22 +++++++++---------
gcc/testsuite/gcc.dg/torture/pr127689-1.c | 28 +++++++++++++++++++++++
2 files changed, 39 insertions(+), 11 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr127689-1.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 2d1161b860b..648bda9bf11 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -214,6 +214,17 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(with { tree utype = unsigned_type_for (TREE_TYPE (@0)); }
(convert (absu:utype @0)))))
+/* (trunc)abs (extend x) --> abs (x) for non-integral types. */
+(simplify
+ (convert (abs (convert@1 @0)))
+ (if (!ANY_INTEGRAL_TYPE_P (TREE_TYPE (@0))
+ && !HONOR_SNANS (@1)
+ && types_match (type, TREE_TYPE (@0))
+ && element_precision (type) < element_precision (TREE_TYPE (@1))
+ && (!VECTOR_TYPE_P (type)
+ || target_supports_op_p (type, ABS_EXPR, optab_default)))
+ (abs @0)))
+
#if GIMPLE
/* Optimize (X + (X >> (prec - 1))) ^ (X >> (prec - 1)) into abs (X). */
(simplify
@@ -10340,17 +10351,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(IFN_COPYSIGN @0 { build_minus_one_cst (type); })
(IFN_COPYSIGN @0 { build_one_cst (type); })))))
-/* (trunc)abs (extend x) --> abs (x) */
-(simplify
- (convert (abs (convert@1 @0)))
- (if (optimize
- && !HONOR_SNANS (@1)
- && types_match (type, TREE_TYPE (@0))
- && element_precision (type) < element_precision (TREE_TYPE (@1))
- && (!VECTOR_TYPE_P (type)
- || target_supports_op_p (type, ABS_EXPR, optab_default)))
- (abs @0)))
-
(for froms (BUILT_IN_FMAF BUILT_IN_FMA BUILT_IN_FMAL)
tos (IFN_FMA IFN_FMA IFN_FMA)
(simplify
diff --git a/gcc/testsuite/gcc.dg/torture/pr127689-1.c
b/gcc/testsuite/gcc.dg/torture/pr127689-1.c
new file mode 100644
index 00000000000..cc169744bf2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr127689-1.c
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-additional-options "-fno-tree-forwprop" } */
+/* PR tree-optimization/127689 */
+
+
+__attribute__((noipa))void check(int v)
+{
+ if (v != -4)
+ __builtin_exit(1);
+}
+int p;
+signed char s, v;
+signed char t = 0x80;
+__attribute__((noipa))
+void y(signed char w) {
+ int t1;
+ t1 = __builtin_abs(t1); //256, 0x80
+ p = t1;
+ s = p;
+ signed char t2 = t1; // -256, 0x80
+ t = t2 % 3; // -2
+ v = 2 * t; // -4
+ check(v);
+}
+int main()
+{
+ y(0x80);
+}
--
2.34.1
