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Don't clear destination if it is used in source

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* config/i386/i386.md (*ctz<mode>2_falsedep_1): Don't clear
	destination if it is used in source.
	(*clz<mode>2_lzcnt_falsedep_1): Likewise.
	(*popcount<mode>2_falsedep_1): Likewise.

From-SVN: r214169
This commit is contained in:
H.J. Lu 2014-08-19 16:26:35 +00:00 committed by H.J. Lu
parent 95204cd5b8
commit b4e8ceb98c
2 changed files with 25 additions and 6 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2014-08-19 H.J. Lu <hongjiu.lu@intel.com>
* config/i386/i386.md (*ctz<mode>2_falsedep_1): Don't clear
destination if it is used in source.
(*clz<mode>2_lzcnt_falsedep_1): Likewise.
(*popcount<mode>2_falsedep_1): Likewise.
2014-08-19 H.J. Lu <hongjiu.lu@intel.com>
PR other/62168

24
gcc/config/i386/i386.md
View File

@ -12269,8 +12269,11 @@
(match_operand:SWI248 1 "nonimmediate_operand")))
(clobber (reg:CC FLAGS_REG))])])
; False dependency happens when destination is only updated by tzcnt,
; lzcnt or popcnt. There is no false dependency when destination is
; also used in source.
(define_insn_and_split "*ctz<mode>2_falsedep_1"
[(set (match_operand:SWI48 0 "register_operand" "=&r")
[(set (match_operand:SWI48 0 "register_operand" "=r")
(ctz:SWI48
(match_operand:SWI48 1 "nonimmediate_operand" "rm")))
(clobber (reg:CC FLAGS_REG))]
@ -12283,7 +12286,10 @@
(ctz:SWI48 (match_dup 1)))
(unspec [(match_dup 0)] UNSPEC_INSN_FALSE_DEP)
(clobber (reg:CC FLAGS_REG))])]
"ix86_expand_clear (operands[0]);")
{
if (!reg_mentioned_p (operands[0], operands[1]))
ix86_expand_clear (operands[0]);
})
(define_insn "*ctz<mode>2_falsedep"
[(set (match_operand:SWI48 0 "register_operand" "=r")
@ -12363,7 +12369,7 @@
"TARGET_LZCNT")
(define_insn_and_split "*clz<mode>2_lzcnt_falsedep_1"
[(set (match_operand:SWI48 0 "register_operand" "=&r")
[(set (match_operand:SWI48 0 "register_operand" "=r")
(clz:SWI48
(match_operand:SWI48 1 "nonimmediate_operand" "rm")))
(clobber (reg:CC FLAGS_REG))]
@ -12376,7 +12382,10 @@
(clz:SWI48 (match_dup 1)))
(unspec [(match_dup 0)] UNSPEC_INSN_FALSE_DEP)
(clobber (reg:CC FLAGS_REG))])]
"ix86_expand_clear (operands[0]);")
{
if (!reg_mentioned_p (operands[0], operands[1]))
ix86_expand_clear (operands[0]);
})
(define_insn "*clz<mode>2_lzcnt_falsedep"
[(set (match_operand:SWI48 0 "register_operand" "=r")
@ -12683,7 +12692,7 @@
"TARGET_POPCNT")
(define_insn_and_split "*popcount<mode>2_falsedep_1"
[(set (match_operand:SWI48 0 "register_operand" "=&r")
[(set (match_operand:SWI48 0 "register_operand" "=r")
(popcount:SWI48
(match_operand:SWI48 1 "nonimmediate_operand" "rm")))
(clobber (reg:CC FLAGS_REG))]
@ -12696,7 +12705,10 @@
(popcount:SWI48 (match_dup 1)))
(unspec [(match_dup 0)] UNSPEC_INSN_FALSE_DEP)
(clobber (reg:CC FLAGS_REG))])]
"ix86_expand_clear (operands[0]);")
{
if (!reg_mentioned_p (operands[0], operands[1]))
ix86_expand_clear (operands[0]);
})
(define_insn "*popcount<mode>2_falsedep"
[(set (match_operand:SWI48 0 "register_operand" "=r")