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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.2.2/] [gcc/] [config/] [sh/] [divcost-analysis] - Blame information for rev 247

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Line No. Rev Author Line
1 38 julius 
Analysis of cycle costs for SH4:
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-> udiv_le128:            5
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-> udiv_ge64k:            6
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-> udiv udiv_25:         10
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-> pos_divisor:           3
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-> pos_result linear:     5
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-> pos_result - -:        5
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-> div_le128:             7
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-> div_ge64k:             9
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sdivsi3 -> udiv_25             13
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udiv25 -> div_ge64k_end:       15
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div_ge64k_end -> rts:          13
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div_le128 -> div_le128_2:       2, r1 latency 3
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udiv_le128 -> div_le128_2:      2, r1 latency 3
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(u)div_le128 -> div_by_1:       9
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(u)div_le128 -> rts:           17
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div_by_1(_neg) -> rts:          4
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div_ge64k -> div_r8:            2
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div_ge64k -> div_ge64k_2:       3
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udiv_ge64k -> udiv_r8:          3
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udiv_ge64k -> div_ge64k_2:      3 + LS
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(u)div_ge64k -> div_ge64k_end: 13
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div_r8 -> div_r8_2:             2
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udiv_r8 -> div_r8_2:            2 + LS
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(u)div_r8 -> rts:              21
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-> - + neg_result:             5
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-> + - neg_result:             5
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-> div_le128_neg:              7
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-> div_ge64k_neg:              9
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-> div_r8_neg:                11
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-> <64k div_ge64k_neg_end:    28
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-> >=64k div_ge64k_neg_end:   22
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div_ge64k_neg_end ft -> rts:  14
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div_r8_neg_end -> rts:         4
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div_r8_neg -> div_r8_neg_end: 18
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div_le128_neg -> div_by_1_neg: 4
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div_le128_neg -> rts          18
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                    absolute divisor range:
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            1  [2..128]  [129..64K) [64K..|divident|/256] >=64K,>|divident/256|
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udiv       18     22         38            32                   30
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sdiv pos:  20     24         41            35                   32
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sdiv neg:  15     25         42            36                   33
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fp-based:
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unsigned: 42 + 3 + 3 (lingering ftrc latency + sts fpul,rx) at caller's site
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signed: 33 + 3 + 3 (lingering ftrc latency + sts fpul,rx) at caller's site
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call-div1:    divisor range:
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              [1..64K)  >= 64K
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unsigned:       63        58
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signed:         76        76
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SFUNC_STATIC call overhead:
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mov.l 0f,r1
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bsrf r1
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SFUNC_GOT call overhead - current:
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mov.l 0f,r1
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mova 0f,r0
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mov.l 1f,r2
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add r1,r0
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mov.l @(r0,r2),r0
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jmp @r0
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; 3 cycles worse than SFUNC_STATIC
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SFUNC_GOT call overhead - improved assembler:
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mov.l 0f,r1
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mova 0f,r0
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mov.l @(r0,r1),r0
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jmp @r0
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; 2 cycles worse than SFUNC_STATIC

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