[llvm] r202195 - R600: Don't unconditionally unroll loops with private memory accesses
Tom Stellard
thomas.stellard at amd.com
Tue Feb 25 13:36:22 PST 2014
Author: tstellar
Date: Tue Feb 25 15:36:21 2014
New Revision: 202195
URL: http://llvm.org/viewvc/llvm-project?rev=202195&view=rev
Log:
R600: Don't unconditionally unroll loops with private memory accesses
This causes the size of the scrypt kernel to explode and eats all the
memory on some systems.
Modified:
llvm/trunk/lib/Target/R600/AMDGPUTargetTransformInfo.cpp
Modified: llvm/trunk/lib/Target/R600/AMDGPUTargetTransformInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/AMDGPUTargetTransformInfo.cpp?rev=202195&r1=202194&r2=202195&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/AMDGPUTargetTransformInfo.cpp (original)
+++ llvm/trunk/lib/Target/R600/AMDGPUTargetTransformInfo.cpp Tue Feb 25 15:36:21 2014
@@ -110,9 +110,13 @@ void AMDGPUTTI::getUnrollingPreferences(
// instructions that make it through to the code generator. allocas
// require us to use indirect addressing, which is slow and prone to
// compiler bugs. If this loop does an address calculation on an
- // alloca ptr, then we want to unconditionally unroll the loop. In most
- // cases, this will make it possible for SROA to eliminate these allocas.
- UP.Threshold = UINT_MAX;
+ // alloca ptr, then we want to use a higher than normal loop unroll
+ // threshold. This will give SROA a better chance to eliminate these
+ // allocas.
+ //
+ // Don't use the maximum allowed value here as it will make some
+ // programs way too big.
+ UP.Threshold = 500;
}
}
}
More information about the llvm-commits
mailing list