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x86: refine when to trigger optimizations

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Checking just the base opcode without also checking this isn't a VEX
encoding, and without there being other insn properties avoiding a match
once respective VEX/XOP/EXEX-encoded insns would appear, is at least
dangerous. Add respective checks. At the same time there's no real need
to check the extension opcode to be None for the 0xA8 form - there's
nothing it can be confused with, and non-VEX-and-alike forms also can't
appear.
This commit is contained in:
Jan Beulich 2020-01-09 11:40:04 +01:00
parent 3f93af6141
commit 72aea32839
2 changed files with 15 additions and 10 deletions
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6
gas/ChangeLog
View File

@ -1,3 +1,9 @@
2020-01-09 Jan Beulich <jbeulich@suse.com>
* config/tc-i386.c (optimize_encoding): Add
is_any_vex_encoding() invocations. Drop respective
i.tm.extension_opcode == None checks.
2020-01-09 Jan Beulich <jbeulich@suse.com>
* config/tc-i386.c (md_assemble): Check RegRex is clear during

19
gas/config/tc-i386.c
View File

@ -3990,13 +3990,13 @@ optimize_encoding (void)
unsigned int j;
if (optimize_for_space
&& !is_any_vex_encoding (&i.tm)
&& i.reg_operands == 1
&& i.imm_operands == 1
&& !i.types[1].bitfield.byte
&& i.op[0].imms->X_op == O_constant
&& fits_in_imm7 (i.op[0].imms->X_add_number)
&& ((i.tm.base_opcode == 0xa8
&& i.tm.extension_opcode == None)
&& (i.tm.base_opcode == 0xa8
|| (i.tm.base_opcode == 0xf6
&& i.tm.extension_opcode == 0x0)))
{
@ -4022,6 +4022,7 @@ optimize_encoding (void)
}
}
else if (flag_code == CODE_64BIT
&& !is_any_vex_encoding (&i.tm)
&& ((i.types[1].bitfield.qword
&& i.reg_operands == 1
&& i.imm_operands == 1
@ -4030,9 +4031,8 @@ optimize_encoding (void)
&& i.tm.extension_opcode == None
&& fits_in_unsigned_long (i.op[0].imms->X_add_number))
|| (fits_in_imm31 (i.op[0].imms->X_add_number)
&& (((i.tm.base_opcode == 0x24
|| i.tm.base_opcode == 0xa8)
&& i.tm.extension_opcode == None)
&& ((i.tm.base_opcode == 0x24
|| i.tm.base_opcode == 0xa8)
|| (i.tm.base_opcode == 0x80
&& i.tm.extension_opcode == 0x4)
|| ((i.tm.base_opcode == 0xf6
@ -4044,13 +4044,11 @@ optimize_encoding (void)
|| (i.types[0].bitfield.qword
&& ((i.reg_operands == 2
&& i.op[0].regs == i.op[1].regs
&& ((i.tm.base_opcode == 0x30
|| i.tm.base_opcode == 0x28)
&& i.tm.extension_opcode == None))
&& (i.tm.base_opcode == 0x30
|| i.tm.base_opcode == 0x28))
|| (i.reg_operands == 1
&& i.operands == 1
&& i.tm.base_opcode == 0x30
&& i.tm.extension_opcode == None)))))
&& i.tm.base_opcode == 0x30)))))
{
/* Optimize: -O:
andq $imm31, %r64 -> andl $imm31, %r32
@ -4091,6 +4089,7 @@ optimize_encoding (void)
}
else if (optimize > 1
&& !optimize_for_space
&& !is_any_vex_encoding (&i.tm)
&& i.reg_operands == 2
&& i.op[0].regs == i.op[1].regs
&& ((i.tm.base_opcode & ~(Opcode_D | 1)) == 0x8