AMDGPUPerfHintAnalysis: reduce indirect and large stride weights

[foad]

Summary

Reduce the default weight for indirect and large stride accesses. Many
graphics shaders are no more than a couple of thousand instructions in
total, so with the old default weight of 1000, even a single indirect or
large stride access would be enough to push them over the 50% threshold.

[rampitec]

Offhand 10 times reduction seems huge. Can you update perfhint.ll to show boundary cases, before and after crossing the threshold?

[arsenm]

Needs test?

llvm/lib/Target/AMDGPU/AMDGPUPerfHintAnalysis.cpp

static cl::opt<unsigned>
     MemBoundThresh("amdgpu-membound-threshold", cl::init(50), cl::Hidden,
                    cl::desc("Function mem bound threshold in %"));
 
 static cl::opt<unsigned>
     LimitWaveThresh("amdgpu-limit-wave-threshold", cl::init(50), cl::Hidden,
                     cl::desc("Kernel limit wave threshold in %"));
 
 static cl::opt<unsigned>
-    IAWeight("amdgpu-indirect-access-weight", cl::init(1000), cl::Hidden,
+    IAWeight("amdgpu-indirect-access-weight", cl::init(100), cl::Hidden,
              cl::desc("Indirect access memory instruction weight"));
 
 static cl::opt<unsigned>
-    LSWeight("amdgpu-large-stride-weight", cl::init(1000), cl::Hidden,
+    LSWeight("amdgpu-large-stride-weight", cl::init(100), cl::Hidden,
              cl::desc("Large stride memory access weight"));
 
 static cl::opt<unsigned>
     LargeStrideThresh("amdgpu-large-stride-threshold", cl::init(64), cl::Hidden,
                       cl::desc("Large stride memory access threshold"));
 
 STATISTIC(NumMemBound, "Number of functions marked as memory bound");
 STATISTIC(NumLimitWave, "Number of functions marked as needing limit wave");