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| author | Roger Sayle <roger@nextmovesoftware.com> | 2022-07-18 07:41:36 +0100 |
|---|---|---|
| committer | Roger Sayle <roger@nextmovesoftware.com> | 2022-07-18 07:41:36 +0100 |
| commit | 43c2505b31adfdef2214318484aaae987fd9e1e0 (patch) | |
| tree | 7b5758f095566ed9b6b767f05068688d2231e65f /gcc | |
| parent | f9da2663f500f473f6ae309e3349a65e6f02001b (diff) | |
| download | gcc-43c2505b31adfdef2214318484aaae987fd9e1e0.zip gcc-43c2505b31adfdef2214318484aaae987fd9e1e0.tar.gz gcc-43c2505b31adfdef2214318484aaae987fd9e1e0.tar.bz2 | |
Fix issue with x86_64_const_vector_operand predicate on x86.
This patch fixes (what I believe is) a latent bug in i386.md's
x86_64_const_vector_operand define_predicate. According to the
documentation, when a predicate is called with rtx operand OP and
machine_mode operand MODE, we can't shouldn't assume that the
MODE is (or has been checked to be) GET_MODE (OP).
The failure mode is that recog can call x86_64_const_vector_operand
on an arbitrary CONST_VECTOR passing a MODE of V2QI_mode, but when
the CONST_VECTOR is in fact V1TImode, it's unsafe to directly call
ix86_convert_const_vector_to_integer, which assumes that the CONST_VECTOR
contains CONST_INTs when it actually contains CONST_WIDE_INTs. The
checks in this define_predicate need to be testing OP's mode, and
ideally confirming that this matches the passed in/specified MODE.
This bug is currently latent, but adding an innocent/unrelated
define_insn, such as "(set (reg:CCC FLAGS_REG) (const_int 0))" to
i386.md can occasionally change the order in which genrecog generates
its tests, then ICEing during bootstrap due to V1TI CONST_VECTORs.
2022-07-18 Roger Sayle <roger@nextmovesoftware.com>
gcc/ChangeLog
* config/i386/predicates.md (x86_64_const_vector_operand):
Check the operand's mode matches the specified mode argument.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/config/i386/predicates.md | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/gcc/config/i386/predicates.md b/gcc/config/i386/predicates.md index c71c453..42053ea 100644 --- a/gcc/config/i386/predicates.md +++ b/gcc/config/i386/predicates.md @@ -1199,6 +1199,10 @@ (define_predicate "x86_64_const_vector_operand" (match_code "const_vector") { + if (mode == VOIDmode) + mode = GET_MODE (op); + else if (GET_MODE (op) != mode) + return false; if (GET_MODE_SIZE (mode) > UNITS_PER_WORD) return false; HOST_WIDE_INT val = ix86_convert_const_vector_to_integer (op, mode); |