diff options
Diffstat (limited to 'lib/Analysis/ValueTracking.cpp')
| -rw-r--r-- | lib/Analysis/ValueTracking.cpp | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/lib/Analysis/ValueTracking.cpp b/lib/Analysis/ValueTracking.cpp index 37d5ad3287..5439bbff26 100644 --- a/lib/Analysis/ValueTracking.cpp +++ b/lib/Analysis/ValueTracking.cpp @@ -1064,12 +1064,15 @@ const Value *llvm::DecomposeGEPExpression(const Value *V, int64_t &BaseOffs, uint64_t Scale = TD->getTypeAllocSize(*GTI); + // Use GetLinearExpression to decompose the index into a C1*V+C2 form. unsigned Width = cast<IntegerType>(Index->getType())->getBitWidth(); APInt IndexScale(Width, 0), IndexOffset(Width, 0); Index = GetLinearExpression(Index, IndexScale, IndexOffset, TD); - Scale *= IndexScale.getZExtValue(); + // The GEP index scale ("Scale") scales C1*V+C2, yielding (C1*V+C2)*Scale. + // This gives us an aggregate computation of (C1*Scale)*V + C2*Scale. BaseOffs += IndexOffset.getZExtValue()*Scale; + Scale *= IndexScale.getZExtValue(); // If we already had an occurrance of this index variable, merge this |