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fix the -g/O3 discrepancy for 32bit compile

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in debug mode, some float operations see their intermediate
values stored in memory rather than staying in the FPU (which
is 80bit precision).

Several fixes are possible (breaking long calculations into
atomic steps for instance), but simpler of all is just about
turning the cost[] array into float* instead of double*.

The code is a tad faster, and i didn't see any major output
size difference.

Change-Id: Icf1f833e15f8ee4ecc7f9a521d07fdc96ef711aa
This commit is contained in:
skal 2012-10-03 15:15:58 +02:00
parent 73ba4357fe
commit a792b913bd
1 changed files with 5 additions and 6 deletions
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11
src/enc/backward_references.c
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@ -459,8 +459,8 @@ static int BackwardReferencesHashChainDistanceOnly(
const int quality = 100;
const int pix_count = xsize * ysize;
const int use_color_cache = (cache_bits > 0);
double* const cost =
(double*)WebPSafeMalloc((uint64_t)pix_count, sizeof(*cost));
float* const cost =
(float*)WebPSafeMalloc((uint64_t)pix_count, sizeof(*cost));
CostModel* cost_model = (CostModel*)malloc(sizeof(*cost_model));
HashChain* hash_chain = (HashChain*)malloc(sizeof(*hash_chain));
VP8LColorCache hashers;
@ -481,7 +481,7 @@ static int BackwardReferencesHashChainDistanceOnly(
goto Error;
}
for (i = 0; i < pix_count; ++i) cost[i] = 1e100;
for (i = 0; i < pix_count; ++i) cost[i] = 1e38f;
// We loop one pixel at a time, but store all currently best points to
// non-processed locations from this point.
@ -509,10 +509,9 @@ static int BackwardReferencesHashChainDistanceOnly(
prev_cost + GetDistanceCost(cost_model, code);
int k;
for (k = 1; k < len; ++k) {
const double cost_val =
distance_cost + GetLengthCost(cost_model, k);
const double cost_val = distance_cost + GetLengthCost(cost_model, k);
if (cost[i + k] > cost_val) {
cost[i + k] = cost_val;
cost[i + k] = (float)cost_val;
dist_array[i + k] = k + 1;
}
}