load are exactly consequtive. This is picked up by other passes, but this
triggers thousands of times in fortran programs that use static locals
(and is thus a compile-time speedup).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23320
91177308-0d34-0410-b5e6-
96231b3b80d8
// None of the following transforms are legal for volatile loads.
if (LI.isVolatile()) return 0;
// None of the following transforms are legal for volatile loads.
if (LI.isVolatile()) return 0;
+
+ // If the instruction immediately before this is a store to the same address,
+ // do a simple form of store->load forwarding.
+ if (&LI.getParent()->front() != &LI) {
+ BasicBlock::iterator BBI = &LI; --BBI;
+ if (StoreInst *SI = dyn_cast<StoreInst>(BBI))
+ if (SI->getOperand(1) == LI.getOperand(0))
+ return ReplaceInstUsesWith(LI, SI->getOperand(0));
+ }
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op))
if (isa<ConstantPointerNull>(GEPI->getOperand(0)) ||
if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(Op))
if (isa<ConstantPointerNull>(GEPI->getOperand(0)) ||