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authorMatthew Malcomson <matthew.malcomson@arm.com>2018-10-16 18:49:36 +0100
committerTamar Christina <tamar.christina@arm.com>2018-10-16 18:50:42 +0100
commit66e6f0b760c2480e4ebdac8169adcee1fc31f689 (patch)
tree8da71d2cbc9b63a880551022a93b47f922619297 /opcodes
parent48dcd4ea064ae86364dacbf4dd7f035fba56151c (diff)
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AArch64: Fix error checking for SIMD udot (by element)
Committed on behalf of Matthew Malcomson: The SIMD UDOT instruction assembly has an unusual operand that selects a single 32 bit element with the mnemonic 4B. This unusual mnemonic is handled by a special operand qualifier and associated qualifier data in `aarch64_opnd_qualifiers`. The current qualifier data describes 4 1-byte elements with the structure {1, 4, 0x0, "4b", OQK_OPD_VARIANT} This makes sense, as the instruction does work on 4 1-byte elements, however some logic in the `operand_general_constraint_met_p` makes assumptions about the range of index allowed when selecting a SIMD_ELEMENT depending on element size. That function reasons that e.g. in order to select a byte-sized element in a 16 byte V register an index must allow selection of one of the 16 elements and hence its range will be in [0,15]. This reasoning breaks with the above description of a 4 part selection of 1 byte elements and allows an index outside the valid [0,3] range, triggering an assert later on in the program in `aarch64_ins_reglane`. vshcmd: > echo 'udot v0.2s, v1.8b, v2.4b[4]' | ../src/binutils-build/gas/as-new -march=armv8.4-a as-new: ../../binutils-gdb/opcodes/aarch64-asm.c:134: aarch64_ins_reglane: Assertion `reglane_index < 4' failed. {standard input}: Assembler messages: {standard input}:1: Internal error (Aborted). Please report this bug. This patch changes the operand qualifier data so that it describes a single 32 bit element. {4, 1, 0x0, "4b", OQK_OPD_VARIANT} Hence the calculation in `operand_general_constraint_met_p` provides the correct answer and the usual error checking machinery is used. vshcmd: > echo 'udot v0.2s, v1.8b, v2.4b[4]' | ../src/binutils-build/gas/as-new -march=armv8.4-a {standard input}: Assembler messages: {standard input}:1: Error: register element index out of range 0 to 3 at operand 3 -- `udot v0.2s,v1.8b,v2.4b[4]'
Diffstat (limited to 'opcodes')
-rw-r--r--opcodes/ChangeLog5
-rw-r--r--opcodes/aarch64-opc.c3
2 files changed, 7 insertions, 1 deletions
diff --git a/opcodes/ChangeLog b/opcodes/ChangeLog
index 42a3469..4f5e200 100644
--- a/opcodes/ChangeLog
+++ b/opcodes/ChangeLog
@@ -1,3 +1,8 @@
+2018-10-16 Matthew Malcomson <matthew.malcomson@arm.com>
+
+ * aarch64-opc.c (struct operand_qualifier_data): Change qualifier data
+ corresponding to AARCH64_OPND_QLF_S_4B qualifier.
+
2018-10-10 Jan Beulich <jbeulich@suse.com>
* i386-gen.c (opcode_modifiers): Drop Size16, Size32, and
diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index 5cd57d5..44d2ca6 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -703,7 +703,7 @@ struct operand_qualifier_data aarch64_opnd_qualifiers[] =
{4, 1, 0x2, "s", OQK_OPD_VARIANT},
{8, 1, 0x3, "d", OQK_OPD_VARIANT},
{16, 1, 0x4, "q", OQK_OPD_VARIANT},
- {1, 4, 0x0, "4b", OQK_OPD_VARIANT},
+ {4, 1, 0x0, "4b", OQK_OPD_VARIANT},
{1, 4, 0x0, "4b", OQK_OPD_VARIANT},
{1, 8, 0x0, "8b", OQK_OPD_VARIANT},
@@ -2527,6 +2527,7 @@ operand_general_constraint_met_p (const aarch64_opnd_info *opnds, int idx,
else
num = 16;
num = num / aarch64_get_qualifier_esize (qualifier) - 1;
+ assert (aarch64_get_qualifier_nelem (qualifier) == 1);
/* Index out-of-range. */
if (!value_in_range_p (opnd->reglane.index, 0, num))