Attached patch allows only SUBREGs as output operands to movstrict
expander and further allows only register operand outputs in various
corresponding splitters. This enforces the restriction, as documented
for STRICT_LOW_PART RTX:
This expression code is used in only one context: as the
destination operand of a 'set' expression. In addition, the
operand of this expression must be a non-paradoxical 'subreg'
expression.
Additionally, the patch removes post-reload calls to movstrict
expander and consequently constructs RTXes involving STRICT_LOW_PART
with hard registers "by hand".
2019-07-30 Uroš Bizjak <ubiz...@gmail.com>
* config/i386/i386.md (movstrict<mode>): Use register_operand
predicate for operand 0. Add expander condition. Assert that
operand 0 is a SUBREG RTX.
(*movstrict<mode>_1): Use register_operand predicate for operand 0.
Update operand constraints and insn condition.
(zero_extend<mode>si2_and): Do not call gen_movstrict<mode>.
(zero_extendqihi2_and): Do not call gen_movstrictqi.
(*setcc_qi_slp): Use register_operand predicate for operand 0.
Update operand 0 constraints.
(setcc_qi_slp splitters): Use register_operand predicate for operand 0.
Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
Committed to mainline SVN.
Uros.
Index: config/i386/i386.md
===================================================================
--- config/i386/i386.md (revision 273873)
+++ config/i386/i386.md (working copy)
@@ -2786,26 +2786,20 @@
(set_attr "bdver1_decode" "double")])
(define_expand "movstrict<mode>"
- [(set (strict_low_part (match_operand:SWI12 0 "nonimmediate_operand"))
+ [(set (strict_low_part (match_operand:SWI12 0 "register_operand"))
(match_operand:SWI12 1 "general_operand"))]
- ""
+ "!TARGET_PARTIAL_REG_STALL || optimize_function_for_size_p (cfun)"
{
- if (TARGET_PARTIAL_REG_STALL && optimize_function_for_speed_p (cfun))
+ gcc_assert (SUBREG_P (operands[0]));
+ if (GET_MODE_CLASS (GET_MODE (SUBREG_REG (operands[0]))) != MODE_INT)
FAIL;
- if (SUBREG_P (operands[0])
- && GET_MODE_CLASS (GET_MODE (SUBREG_REG (operands[0]))) != MODE_INT)
- FAIL;
- /* Don't generate memory->memory moves, go through a register */
- if (MEM_P (operands[0]) && MEM_P (operands[1]))
- operands[1] = force_reg (<MODE>mode, operands[1]);
})
(define_insn "*movstrict<mode>_1"
[(set (strict_low_part
- (match_operand:SWI12 0 "nonimmediate_operand" "+<r>m,<r>"))
- (match_operand:SWI12 1 "general_operand" "<r>n,m"))]
- "(!TARGET_PARTIAL_REG_STALL || optimize_function_for_size_p (cfun))
- && !(MEM_P (operands[0]) && MEM_P (operands[1]))"
+ (match_operand:SWI12 0 "register_operand" "+<r>"))
+ (match_operand:SWI12 1 "general_operand" "<r>mn"))]
+ "!TARGET_PARTIAL_REG_STALL || optimize_function_for_size_p (cfun)"
"mov{<imodesuffix>}\t{%1, %0|%0, %1}"
[(set_attr "type" "imov")
(set_attr "mode" "<MODE>")])
@@ -4011,8 +4005,10 @@
ix86_expand_clear (operands[0]);
gcc_assert (!TARGET_PARTIAL_REG_STALL);
- emit_insn (gen_movstrict<mode>
- (gen_lowpart (<MODE>mode, operands[0]), operands[1]));
+ emit_insn (gen_rtx_SET
+ (gen_rtx_STRICT_LOW_PART
+ (VOIDmode, gen_lowpart (<MODE>mode, operands[0])),
+ operands[1]));
DONE;
}
@@ -4063,8 +4059,10 @@
ix86_expand_clear (operands[0]);
gcc_assert (!TARGET_PARTIAL_REG_STALL);
- emit_insn (gen_movstrictqi
- (gen_lowpart (QImode, operands[0]), operands[1]));
+ emit_insn (gen_rtx_SET
+ (gen_rtx_STRICT_LOW_PART
+ (VOIDmode, gen_lowpart (QImode, operands[0])),
+ operands[1]));
DONE;
}
@@ -11835,7 +11833,7 @@
(set_attr "mode" "QI")])
(define_insn "*setcc_qi_slp"
- [(set (strict_low_part (match_operand:QI 0 "nonimmediate_operand" "+qm"))
+ [(set (strict_low_part (match_operand:QI 0 "register_operand" "+q"))
(match_operator:QI 1 "ix86_comparison_operator"
[(reg FLAGS_REG) (const_int 0)]))]
""
@@ -11864,7 +11862,7 @@
})
(define_split
- [(set (strict_low_part (match_operand:QI 0 "nonimmediate_operand"))
+ [(set (strict_low_part (match_operand:QI 0 "register_operand"))
(ne:QI (match_operator 1 "ix86_comparison_operator"
[(reg FLAGS_REG) (const_int 0)])
(const_int 0)))]
@@ -11896,7 +11894,7 @@
})
(define_split
- [(set (strict_low_part (match_operand:QI 0 "nonimmediate_operand"))
+ [(set (strict_low_part (match_operand:QI 0 "register_operand"))
(eq:QI (match_operator 1 "ix86_comparison_operator"
[(reg FLAGS_REG) (const_int 0)])
(const_int 0)))]
