[gcc r11-9602] c++: Fix up constant expression __builtin_convertvector folding [PR104472]
Jakub Jelinek
jakub@gcc.gnu.org
Sat Feb 19 08:02:45 GMT 2022
https://gcc.gnu.org/g:784deb1671629734322640520a7421106194f20a
commit r11-9602-g784deb1671629734322640520a7421106194f20a
Author: Jakub Jelinek <jakub@redhat.com>
Date: Fri Feb 11 13:52:44 2022 +0100
c++: Fix up constant expression __builtin_convertvector folding [PR104472]
The following testcase ICEs, because due to the -frounding-math
fold_const_call fails, which is it returns NULL, and returning NULL from
cxx_eval* is wrong, all the callers rely on them to either return folded
value or original with *non_constant_p = true.
The following patch does that, and additionally falls through into the
default case where there is diagnostics for the !ctx->quiet case too.
2022-02-11 Jakub Jelinek <jakub@redhat.com>
PR c++/104472
* constexpr.c (cxx_eval_internal_function) <case IFN_VEC_CONVERT>:
Only return fold_const_call result if it is non-NULL. Otherwise
fall through into the default: case to return t, set *non_constant_p
and emit diagnostics if needed.
* g++.dg/cpp0x/constexpr-104472.C: New test.
(cherry picked from commit 84993d94e13ad2ab3aee151bb5a5e767cf75d51e)
Diff:
---
gcc/cp/constexpr.c | 9 +++------
gcc/testsuite/g++.dg/cpp0x/constexpr-104472.C | 9 +++++++++
2 files changed, 12 insertions(+), 6 deletions(-)
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 57decc97455..c27331dd6ad 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -1757,13 +1757,10 @@ cxx_eval_internal_function (const constexpr_ctx *ctx, tree t,
false, non_constant_p,
overflow_p);
if (TREE_CODE (arg) == VECTOR_CST)
- return fold_const_call (CFN_VEC_CONVERT, TREE_TYPE (t), arg);
- else
- {
- *non_constant_p = true;
- return t;
- }
+ if (tree r = fold_const_call (CFN_VEC_CONVERT, TREE_TYPE (t), arg))
+ return r;
}
+ /* FALLTHRU */
default:
if (!ctx->quiet)
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-104472.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-104472.C
new file mode 100644
index 00000000000..c9c8bf414fe
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-104472.C
@@ -0,0 +1,9 @@
+// PR c++/104472
+// { dg-options "-O2 -frounding-math" }
+// { dg-add-options float16 }
+// { dg-require-effective-target float16 }
+
+typedef short __attribute__((__vector_size__ (16))) V;
+typedef _Float16 __attribute__((__vector_size__ (16))) F;
+
+V v = __builtin_convertvector (__builtin_convertvector ((V){5534}, F), V) < 8;
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