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swr/rast: don't use 32-bit gathers for elements < 32-bits in size

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Using a gather for elements less than 32-bits in size can cause
pagefaults when loading the last elements in a page-aligned-sized
buffer.

Reviewed-by: Bruce Cherniak <bruce.cherniak@intel.com>
This commit is contained in:
Tim Rowley
2018-01-03 11:58:50 -06:00
parent f5f1bbcb5c
commit 3d4d34e380
1 changed files with 60 additions and 1 deletions
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src/gallium/drivers/swr/rasterizer/jitter/fetch_jit.cpp
+60 -1
View File
@@ -741,7 +741,66 @@ void FetchJit::CreateGatherOddFormats(SWR_FORMAT format, Value* pMask, Value* pB
// only works if pixel size is <= 32bits
SWR_ASSERT(info.bpp <= 32);
Value *pGather = GATHERDD(VIMMED1(0), pBase, pOffsets, pMask);
Value *pGather;
if (info.bpp == 32)
{
pGather = GATHERDD(VIMMED1(0), pBase, pOffsets, pMask);
}
else
{
// Can't use 32-bit gather for items less than 32-bits, could cause page faults.
Value *pMem = ALLOCA(mSimdInt32Ty);
STORE(VIMMED1(0u), pMem);
pBase = BITCAST(pBase, PointerType::get(mInt8Ty, 0));
Value* pDstMem = BITCAST(pMem, mInt32PtrTy);
for (uint32_t lane = 0; lane < mVWidth; ++lane)
{
// Get index
Value* index = VEXTRACT(pOffsets, C(lane));
Value* mask = VEXTRACT(pMask, C(lane));
switch (info.bpp)
{
case 8:
{
Value* pDst = BITCAST(GEP(pDstMem, C(lane)), PointerType::get(mInt8Ty, 0));
Value* pSrc = BITCAST(GEP(pBase, index), PointerType::get(mInt8Ty, 0));
STORE(LOAD(SELECT(mask, pSrc, pDst)), pDst);
break;
}
case 16:
{
Value* pDst = BITCAST(GEP(pDstMem, C(lane)), PointerType::get(mInt16Ty, 0));
Value* pSrc = BITCAST(GEP(pBase, index), PointerType::get(mInt16Ty, 0));
STORE(LOAD(SELECT(mask, pSrc, pDst)), pDst);
break;
}
break;
case 24:
{
// First 16-bits of data
Value* pDst = BITCAST(GEP(pDstMem, C(lane)), PointerType::get(mInt16Ty, 0));
Value* pSrc = BITCAST(GEP(pBase, index), PointerType::get(mInt16Ty, 0));
STORE(LOAD(SELECT(mask, pSrc, pDst)), pDst);
// Last 8-bits of data
pDst = BITCAST(GEP(pDst, C(1)), PointerType::get(mInt8Ty, 0));
pSrc = BITCAST(GEP(pSrc, C(1)), PointerType::get(mInt8Ty, 0));
STORE(LOAD(SELECT(mask, pSrc, pDst)), pDst);
break;
}
default:
SWR_INVALID("Shouldn't have BPP = %d now", info.bpp);
break;
}
}
pGather = LOAD(pMem);
}
for (uint32_t comp = 0; comp < 4; ++comp)
{