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authorJakub Jelinek <jakub@redhat.com>2023-10-18 17:01:26 +0200
committerJakub Jelinek <jakub@redhat.com>2023-10-18 17:01:26 +0200
commitbc4bd69faf986326f6b0fd0400cdd6871577afd1 (patch)
tree52a289c6f1627c4b3242d24903767d923f579a68 /gcc/cse.cc
parentef10cb8683ae60c161eb88df381e02f95f6e3e30 (diff)
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cse: Workaround GCC < 5 bug in cse_insn [PR111852]
Before the r5-3834 commit for PR63362, GCC 4.8-4.9 refuses to compile cse.cc which contains a variable with rtx_def type, because rtx_def contains a union with poly_uint16 element. poly_int template has defaulted default constructor and a variadic template constructor which could have empty parameter pack. GCC < 5 treated it as non-trivially constructible class and deleted rtunion and rtx_def default constructors. For the cse_insn purposes, all we need is a variable with size and alignment of rtx_def, not necessarily rtx_def itself, which we then memset to 0 and fill in like rtx is normally allocated from heap, so this patch for GCC_VERSION < 5000 uses an unsigned char array of the right size/alignment. 2023-10-18 Jakub Jelinek <jakub@redhat.com> PR bootstrap/111852 * cse.cc (cse_insn): Add workaround for GCC 4.8-4.9, instead of using rtx_def type for memory_extend_buf, use unsigned char arrayy with size of rtx_def and its alignment.
Diffstat (limited to 'gcc/cse.cc')
-rw-r--r--gcc/cse.cc7
1 files changed, 7 insertions, 0 deletions
diff --git a/gcc/cse.cc b/gcc/cse.cc
index c468700..f9603fd 100644
--- a/gcc/cse.cc
+++ b/gcc/cse.cc
@@ -4951,8 +4951,15 @@ cse_insn (rtx_insn *insn)
&& is_a <scalar_int_mode> (mode, &int_mode)
&& (extend_op = load_extend_op (int_mode)) != UNKNOWN)
{
+#if GCC_VERSION >= 5000
struct rtx_def memory_extend_buf;
rtx memory_extend_rtx = &memory_extend_buf;
+#else
+ /* Workaround GCC < 5 bug, fixed in r5-3834 as part of PR63362
+ fix. */
+ alignas (rtx_def) unsigned char memory_extended_buf[sizeof (rtx_def)];
+ rtx memory_extend_rtx = (rtx) &memory_extended_buf[0];
+#endif
/* Set what we are trying to extend and the operation it might
have been extended with. */