* [committed] i386: Clear stack protector scratch with zero/sign-extend instruction
@ 2023-11-10 15:35 Uros Bizjak
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From: Uros Bizjak @ 2023-11-10 15:35 UTC (permalink / raw)
To: gcc-patches
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Use unrelated register initializations using zero/sign-extend instructions
to clear stack protector scratch register.
Handle only SI -> DImode extensions for 64-bit targets, as this is the
only extension that triggers the peephole in a non-negligible number.
Also use explicit check for word_mode instead of mode iterator in peephole2
patterns to avoid pattern explosion.
gcc/ChangeLog:
* config/i386/i386.md (stack_protect_set_1 peephole2):
Explicitly check operand 2 for word_mode.
(stack_protect_set_1 peephole2 #2): Ditto.
(stack_protect_set_2 peephole2): Ditto.
(stack_protect_set_3 peephole2): Ditto.
(*stack_protect_set_4z_<mode>_di): New insn pattern.
(*stack_protect_set_4s_<mode>_di): Ditto.
(stack_protect_set_4 peephole2): New peephole2 pattern to
substitute stack protector scratch register clear with unrelated
register initialization involving zero/sign-extend instruction.
Bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
Uros.
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diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index 046b6b7919e..01fc6ecc351 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -24335,11 +24335,12 @@ (define_peephole2
[(parallel [(set (match_operand:PTR 0 "memory_operand")
(unspec:PTR [(match_operand:PTR 1 "memory_operand")]
UNSPEC_SP_SET))
- (set (match_operand:W 2 "general_reg_operand") (const_int 0))
+ (set (match_operand 2 "general_reg_operand") (const_int 0))
(clobber (reg:CC FLAGS_REG))])
(set (match_operand 3 "general_reg_operand")
(match_operand 4 "const0_operand"))]
- "GET_MODE_SIZE (GET_MODE (operands[3])) <= UNITS_PER_WORD
+ "GET_MODE (operands[2]) == word_mode
+ && GET_MODE_SIZE (GET_MODE (operands[3])) <= UNITS_PER_WORD
&& peep2_reg_dead_p (0, operands[3])
&& peep2_reg_dead_p (1, operands[2])"
[(parallel [(set (match_dup 0)
@@ -24395,11 +24396,12 @@ (define_peephole2
[(parallel [(set (match_operand:PTR 0 "memory_operand")
(unspec:PTR [(match_operand:PTR 1 "memory_operand")]
UNSPEC_SP_SET))
- (set (match_operand:W 2 "general_reg_operand") (const_int 0))
+ (set (match_operand 2 "general_reg_operand") (const_int 0))
(clobber (reg:CC FLAGS_REG))])
(set (match_operand:SWI48 3 "general_reg_operand")
(match_operand:SWI48 4 "general_gr_operand"))]
- "peep2_reg_dead_p (0, operands[3])
+ "GET_MODE (operands[2]) == word_mode
+ && peep2_reg_dead_p (0, operands[3])
&& peep2_reg_dead_p (1, operands[2])"
[(parallel [(set (match_dup 0)
(unspec:PTR [(match_dup 1)] UNSPEC_SP_SET))
@@ -24411,9 +24413,10 @@ (define_peephole2
(parallel [(set (match_operand:PTR 0 "memory_operand")
(unspec:PTR [(match_operand:PTR 1 "memory_operand")]
UNSPEC_SP_SET))
- (set (match_operand:W 2 "general_reg_operand") (const_int 0))
+ (set (match_operand 2 "general_reg_operand") (const_int 0))
(clobber (reg:CC FLAGS_REG))])]
- "peep2_reg_dead_p (0, operands[3])
+ "GET_MODE (operands[2]) == word_mode
+ && peep2_reg_dead_p (0, operands[3])
&& peep2_reg_dead_p (2, operands[2])
&& !reg_mentioned_p (operands[3], operands[0])
&& !reg_mentioned_p (operands[3], operands[1])"
@@ -24448,16 +24451,71 @@ (define_peephole2
[(parallel [(set (match_operand:PTR 0 "memory_operand")
(unspec:PTR [(match_operand:PTR 1 "memory_operand")]
UNSPEC_SP_SET))
- (set (match_operand:W 2 "general_reg_operand") (const_int 0))
+ (set (match_operand 2 "general_reg_operand") (const_int 0))
(clobber (reg:CC FLAGS_REG))])
(set (match_operand:SWI48 3 "general_reg_operand")
(match_operand:SWI48 4 "address_no_seg_operand"))]
- "peep2_reg_dead_p (0, operands[3])
+ "GET_MODE (operands[2]) == word_mode
+ && peep2_reg_dead_p (0, operands[3])
&& peep2_reg_dead_p (1, operands[2])"
[(parallel [(set (match_dup 0)
(unspec:PTR [(match_dup 1)] UNSPEC_SP_SET))
(set (match_dup 3) (match_dup 4))])])
+(define_insn "*stack_protect_set_4z_<mode>_di"
+ [(set (match_operand:PTR 0 "memory_operand" "=m")
+ (unspec:PTR [(match_operand:PTR 3 "memory_operand" "m")]
+ UNSPEC_SP_SET))
+ (set (match_operand:DI 1 "register_operand" "=&r")
+ (zero_extend:DI (match_operand:SI 2 "nonimmediate_operand" "rm")))]
+ "TARGET_64BIT && reload_completed"
+{
+ output_asm_insn ("mov{<imodesuffix>}\t{%3, %<k>1|%<k>1, %3}", operands);
+ output_asm_insn ("mov{<imodesuffix>}\t{%<k>1, %0|%0, %<k>1}", operands);
+ if (ix86_use_lea_for_mov (insn, operands + 1))
+ return "lea{l}\t{%E2, %k1|%k1, %E2}";
+ else
+ return "mov{l}\t{%2, %k1|%k1, %2}";
+}
+ [(set_attr "type" "multi")
+ (set_attr "length" "24")])
+
+(define_insn "*stack_protect_set_4s_<mode>_di"
+ [(set (match_operand:PTR 0 "memory_operand" "=m,m")
+ (unspec:PTR [(match_operand:PTR 3 "memory_operand" "m,m")]
+ UNSPEC_SP_SET))
+ (set (match_operand:DI 1 "register_operand" "=&a,&r")
+ (sign_extend:DI (match_operand:SI 2 "nonimmediate_operand" "0,rm")))]
+ "TARGET_64BIT && reload_completed"
+{
+ output_asm_insn ("mov{<imodesuffix>}\t{%3, %<k>1|%<k>1, %3}", operands);
+ output_asm_insn ("mov{<imodesuffix>}\t{%<k>1, %0|%0, %<k>1}", operands);
+ if (which_alternative)
+ return "movs{lq|x}\t{%2, %1|%1, %2}";
+ else
+ return "{cltq|cdqe}";
+}
+ [(set_attr "type" "multi")
+ (set_attr "length" "24")])
+
+(define_peephole2
+ [(parallel [(set (match_operand:PTR 0 "memory_operand")
+ (unspec:PTR [(match_operand:PTR 1 "memory_operand")]
+ UNSPEC_SP_SET))
+ (set (match_operand 2 "general_reg_operand") (const_int 0))
+ (clobber (reg:CC FLAGS_REG))])
+ (set (match_operand:DI 3 "general_reg_operand")
+ (any_extend:DI
+ (match_operand:SI 4 "nonimmediate_gr_operand")))]
+ "TARGET_64BIT
+ && GET_MODE (operands[2]) == word_mode
+ && peep2_reg_dead_p (0, operands[3])
+ && peep2_reg_dead_p (1, operands[2])"
+ [(parallel [(set (match_dup 0)
+ (unspec:PTR [(match_dup 1)] UNSPEC_SP_SET))
+ (set (match_dup 3)
+ (any_extend:DI (match_dup 4)))])])
+
(define_expand "stack_protect_test"
[(match_operand 0 "memory_operand")
(match_operand 1 "memory_operand")
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2023-11-10 15:35 [committed] i386: Clear stack protector scratch with zero/sign-extend instruction Uros Bizjak
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