From 43c2505b31adfdef2214318484aaae987fd9e1e0 Mon Sep 17 00:00:00 2001 From: Roger Sayle Date: Mon, 18 Jul 2022 07:41:36 +0100 Subject: [PATCH] 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 gcc/ChangeLog * config/i386/predicates.md (x86_64_const_vector_operand): Check the operand's mode matches the specified mode argument. --- gcc/config/i386/predicates.md | 4 ++++ 1 file changed, 4 insertions(+) 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); -- 2.7.4