The following properly checks expr_no_side_effects_p on two patterns
that turns a conditionally evaluated operand into unconditonal.
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
PR middle-end/123887
* match.pd ((zero_one ==/!= 0) ? .. z <op> y .. -> zero_one * z ..):
Check evaluating z unconditionally has no side-effects, like
trapping.
* gcc.dg/torture/pr123887.c: New testcase.
---
gcc/match.pd | 6 ++++--
gcc/testsuite/gcc.dg/torture/pr123887.c | 14 ++++++++++++++
2 files changed, 18 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr123887.c
diff --git a/gcc/match.pd b/gcc/match.pd
index 05e8ea7a229..9b2da2be4c5 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -5178,7 +5178,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(op:c @2 @1))
(if (INTEGRAL_TYPE_P (type)
&& TYPE_PRECISION (type) > 1
- && (INTEGRAL_TYPE_P (TREE_TYPE (@0))))
+ && INTEGRAL_TYPE_P (TREE_TYPE (@0))
+ && expr_no_side_effects_p (@2))
(op (mult (convert:type @0) @2) @1))))
/* (zero_one != 0) ? z <op> y : y -> ((typeof(y))zero_one * z) <op> y */
@@ -5190,7 +5191,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
@1)
(if (INTEGRAL_TYPE_P (type)
&& TYPE_PRECISION (type) > 1
- && (INTEGRAL_TYPE_P (TREE_TYPE (@0))))
+ && INTEGRAL_TYPE_P (TREE_TYPE (@0))
+ && expr_no_side_effects_p (@2))
(op (mult (convert:type @0) @2) @1))))
/* ?: Value replacement. */
diff --git a/gcc/testsuite/gcc.dg/torture/pr123887.c
b/gcc/testsuite/gcc.dg/torture/pr123887.c
new file mode 100644
index 00000000000..c2a9659c5b5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr123887.c
@@ -0,0 +1,14 @@
+/* { dg-do run } */
+
+typedef struct {
+ unsigned s;
+} struct_t;
+
+struct_t *p;
+bool cond;
+int v = 1;
+int main()
+{
+ int u = 1 + (cond ? p->s : 0);
+ return u - v;
+}
--
2.51.0
