4 Commits

Author	SHA1	Message	Date
Hal Finkel	4d94930bcb	Consider (x == -1) unlikely in BranchProbabilityInfo ... This adds another heuristic to BPI, similar to the existing heuristic that considers (x == 0) unlikely to be true. As suggested in the PACT'98 paper by Deitrich, Cheng, and Hwu, -1 is often used to indicate an invalid index, and equality comparisons with -1 are also unlikely to succeed. Local experimentation supports this hypothesis: This yields a 1-2% speedup in the test-suite sqlite benchmark on the PPC A2 core, with no significant regressions. llvm-svn: 193855	2013-11-01 10:58:22 +00:00
Diego Novillo	c63995394d	Add a new function attribute 'cold' to functions. ... Other than recognizing the attribute, the patch does little else. It changes the branch probability analyzer so that edges into blocks postdominated by a cold function are given low weight. Added analysis and code generation tests. Added documentation for the new attribute. llvm-svn: 182638	2013-05-24 12:26:52 +00:00
Manman Ren	cf10446ffa	BranchProb: modify the definition of an edge in BranchProbabilityInfo to handle ... the case of multiple edges from one block to another. A simple example is a switch statement with multiple values to the same destination. The definition of an edge is modified from a pair of blocks to a pair of PredBlock and an index into the successors. Also set the weight correctly when building SelectionDAG from LLVM IR, especially when converting a Switch. IntegersSubsetMapping is updated to calculate the weight for each cluster. llvm-svn: 162572	2012-08-24 18:14:27 +00:00
Chandler Carruth	1c8ace0e89	Teach the BranchProbabilityInfo pass to print its results, and use that ... to bring it under direct test instead of merely indirectly testing it in the BlockFrequencyInfo pass. The next step is to start adding tests for the various heuristics employed, and to start fixing those heuristics once they're under test. llvm-svn: 142778	2011-10-23 21:21:50 +00:00