https://gcc.gnu.org/g:b07f8a301158e53717b8688cc8ea430b6f02574c
commit r15-3087-gb07f8a301158e53717b8688cc8ea430b6f02574c
Author: Andrew Pinski <quic_apin...@quicinc.com>
Date: Wed Aug 21 17:41:38 2024 -0700
fold: Fix `a * 1j` if a has side effects [PR116454]
The problem here was a missing save_expr around arg0 since
it is used twice, once in REALPART_EXPR and once in IMAGPART_EXPR.
Thia adds the save_expr and reformats the code slightly so it is a
little easier to understand. It excludes the case when arg0 is
a COMPLEX_EXPR since in that case we'll end up with the distinct
real and imaginary parts. This is important to retain early
optimization in some testcases.
Bootstapped and tested on x86_64-linux-gnu with no regressions.
PR middle-end/116454
gcc/ChangeLog:
* fold-const.cc (fold_binary_loc): Fix `a * +-1i`
by wrapping arg0 with save_expr when it is not COMPLEX_EXPR.
gcc/testsuite/ChangeLog:
* gcc.dg/torture/pr116454-1.c: New test.
* gcc.dg/torture/pr116454-2.c: New test.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
Co-Authored-By: Richard Biener <rguent...@suse.de>
Diff:
---
gcc/fold-const.cc | 32 +++++++++++++++++++++----------
gcc/testsuite/gcc.dg/torture/pr116454-1.c | 16 ++++++++++++++++
gcc/testsuite/gcc.dg/torture/pr116454-2.c | 12 ++++++++++++
3 files changed, 50 insertions(+), 10 deletions(-)
diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
index 8908e7381e72..ccc499af6617 100644
--- a/gcc/fold-const.cc
+++ b/gcc/fold-const.cc
@@ -12093,17 +12093,29 @@ fold_binary_loc (location_t loc, enum tree_code code,
tree type,
{
tree rtype = TREE_TYPE (TREE_TYPE (arg0));
if (real_onep (TREE_IMAGPART (arg1)))
- return
- fold_build2_loc (loc, COMPLEX_EXPR, type,
- negate_expr (fold_build1_loc (loc, IMAGPART_EXPR,
- rtype, arg0)),
- fold_build1_loc (loc, REALPART_EXPR, rtype,
arg0));
+ {
+ if (TREE_CODE (arg0) != COMPLEX_EXPR)
+ arg0 = save_expr (arg0);
+ tree iarg0 = fold_build1_loc (loc, IMAGPART_EXPR,
+ rtype, arg0);
+ tree rarg0 = fold_build1_loc (loc, REALPART_EXPR,
+ rtype, arg0);
+ return fold_build2_loc (loc, COMPLEX_EXPR, type,
+ negate_expr (iarg0),
+ rarg0);
+ }
else if (real_minus_onep (TREE_IMAGPART (arg1)))
- return
- fold_build2_loc (loc, COMPLEX_EXPR, type,
- fold_build1_loc (loc, IMAGPART_EXPR, rtype,
arg0),
- negate_expr (fold_build1_loc (loc, REALPART_EXPR,
- rtype, arg0)));
+ {
+ if (TREE_CODE (arg0) != COMPLEX_EXPR)
+ arg0 = save_expr (arg0);
+ tree iarg0 = fold_build1_loc (loc, IMAGPART_EXPR,
+ rtype, arg0);
+ tree rarg0 = fold_build1_loc (loc, REALPART_EXPR,
+ rtype, arg0);
+ return fold_build2_loc (loc, COMPLEX_EXPR, type,
+ iarg0,
+ negate_expr (rarg0));
+ }
}
/* Optimize z * conj(z) for floating point complex numbers.
diff --git a/gcc/testsuite/gcc.dg/torture/pr116454-1.c
b/gcc/testsuite/gcc.dg/torture/pr116454-1.c
new file mode 100644
index 000000000000..6210dcce4a42
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr116454-1.c
@@ -0,0 +1,16 @@
+/* { dg-do run } */
+/* { dg-additional-options "-ffast-math" } */
+
+static int t = 0;
+_Complex float f()
+{
+ t++;
+ return 0;
+}
+int main() {
+ t = 0;
+ /* Would cause f() to be incorrectly invoked twice. */
+ f() * 1j;
+ if (t != 1)
+ __builtin_abort();
+}
diff --git a/gcc/testsuite/gcc.dg/torture/pr116454-2.c
b/gcc/testsuite/gcc.dg/torture/pr116454-2.c
new file mode 100644
index 000000000000..a1e1604e6169
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr116454-2.c
@@ -0,0 +1,12 @@
+/* { dg-do run } */
+/* { dg-additional-options "-ffast-math" } */
+_Complex float arr[2];
+
+int main() {
+ _Complex float *ptr;
+ ptr = arr;
+ *++ptr * 1j;
+ /* ptr should only increment once, not twice. */
+ if (ptr != arr + 1)
+ __builtin_abort ();
+}
