llvm-6502/test/Analysis
Arnold Schwaighofer 3d5f96ee1b BasicAA: Recognize cyclic NoAlias phis
Enhances basic alias analysis to recognize phis whose first incoming values are
NoAlias and whose other incoming values are just the phi node itself through
some amount of recursion.

Example: With this change basicaa reports that ptr_phi and ptr_phi2 do not alias
each other.

bb:
 ptr = ptr2 + 1

loop:
  ptr_phi = phi [bb, ptr], [loop, ptr_plus_one]
  ptr2_phi = phi [bb, ptr2], [loop, ptr2_plus_one]
  ...
  ptr_plus_one = gep ptr_phi, 1
  ptr2_plus_one = gep ptr2_phi, 1

This enables the elimination of one load in code like the following:

extern int foo;

int test_noalias(int *ptr, int num, int* coeff) {
  int *ptr2 = ptr;
  int result = (*ptr++) * (*coeff--);
  while (num--) {
    *ptr2++ = *ptr;
    result +=  (*coeff--) * (*ptr++);
  }
  *ptr = foo;
  return result;
}

Part 2/2 of fix for PR13564.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163319 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06 14:41:53 +00:00
..
BasicAA BasicAA: Recognize cyclic NoAlias phis 2012-09-06 14:41:53 +00:00
BlockFrequencyInfo
BranchProbabilityInfo BranchProb: modify the definition of an edge in BranchProbabilityInfo to handle 2012-08-24 18:14:27 +00:00
CallGraph
Dominators
GlobalsModRef
LoopDependenceAnalysis
LoopInfo
PostDominators
Profiling llvm/test/Analysis/Profiling: Mark 3 of them as REQUIRES: loadable_module. 2012-08-29 00:37:46 +00:00
RegionInfo
ScalarEvolution
TypeBasedAliasAnalysis