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| author | Hans-Peter Nilsson <hp@axis.com> | 2012-07-12 21:14:14 +0000 |
|---|---|---|
| committer | Hans-Peter Nilsson <hp@gcc.gnu.org> | 2012-07-12 21:14:14 +0000 |
| commit | e098c1696289d3d935d13ebed803c5b32045ba6d (patch) | |
| tree | dc588155e6de500b6c1e343812291707762bbd90 /gcc/rtlanal.c | |
| parent | 8c15b4b04f81d00c916aeb7a5ba186722d4a4b2d (diff) | |
| download | gcc-e098c1696289d3d935d13ebed803c5b32045ba6d.zip gcc-e098c1696289d3d935d13ebed803c5b32045ba6d.tar.gz gcc-e098c1696289d3d935d13ebed803c5b32045ba6d.tar.bz2 | |
re PR rtl-optimization/53176 (gcc.dg/lower-subreg-1.c FAILs)
PR rtl-optimization/53176
* rtlanal.c (rtx_cost): Adjust default cost for X with a
UNITS_PER_WORD factor for all X according to the size of
its mode, not just for SUBREGs with untieable modes.
Handle SET. Use factor * factor for MULT, DIV, UDIV,
MOD, UMOD.
From-SVN: r189441
Diffstat (limited to 'gcc/rtlanal.c')
| -rw-r--r-- | gcc/rtlanal.c | 27 |
1 files changed, 22 insertions, 5 deletions
diff --git a/gcc/rtlanal.c b/gcc/rtlanal.c index f3527b4..8f52e4f 100644 --- a/gcc/rtlanal.c +++ b/gcc/rtlanal.c @@ -3755,10 +3755,17 @@ rtx_cost (rtx x, enum rtx_code outer_code, int opno, bool speed) enum rtx_code code; const char *fmt; int total; + int factor; if (x == 0) return 0; + /* A size N times larger than UNITS_PER_WORD likely needs N times as + many insns, taking N times as long. */ + factor = GET_MODE_SIZE (GET_MODE (x)) / UNITS_PER_WORD; + if (factor == 0) + factor = 1; + /* Compute the default costs of certain things. Note that targetm.rtx_costs can override the defaults. */ @@ -3766,20 +3773,31 @@ rtx_cost (rtx x, enum rtx_code outer_code, int opno, bool speed) switch (code) { case MULT: - total = COSTS_N_INSNS (5); + /* Multiplication has time-complexity O(N*N), where N is the + number of units (translated from digits) when using + schoolbook long multiplication. */ + total = factor * factor * COSTS_N_INSNS (5); break; case DIV: case UDIV: case MOD: case UMOD: - total = COSTS_N_INSNS (7); + /* Similarly, complexity for schoolbook long division. */ + total = factor * factor * COSTS_N_INSNS (7); break; case USE: /* Used in combine.c as a marker. */ total = 0; break; + case SET: + /* A SET doesn't have a mode, so let's look at the SET_DEST to get + the mode for the factor. */ + factor = GET_MODE_SIZE (GET_MODE (SET_DEST (x))) / UNITS_PER_WORD; + if (factor == 0) + factor = 1; + /* Pass through. */ default: - total = COSTS_N_INSNS (1); + total = factor * COSTS_N_INSNS (1); } switch (code) @@ -3792,8 +3810,7 @@ rtx_cost (rtx x, enum rtx_code outer_code, int opno, bool speed) /* If we can't tie these modes, make this expensive. The larger the mode, the more expensive it is. */ if (! MODES_TIEABLE_P (GET_MODE (x), GET_MODE (SUBREG_REG (x)))) - return COSTS_N_INSNS (2 - + GET_MODE_SIZE (GET_MODE (x)) / UNITS_PER_WORD); + return COSTS_N_INSNS (2 + factor); break; default: |