Some enhancements for memcpy / memset inline expansion.
1. Teach it to use overlapping unaligned load / store to copy / set the trailing
bytes. e.g. On 86, use two pairs of movups / movaps for 17 - 31 byte copies.
2. Use f64 for memcpy / memset on targets where i64 is not legal but f64 is. e.g.
x86 and ARM.
3. When memcpy from a constant string, do *not* replace the load with a constant
if it's not possible to materialize an integer immediate with a single
instruction (required a new target hook: TLI.isIntImmLegal()).
4. Use unaligned load / stores more aggressively if target hooks indicates they
are "fast".
5. Update ARM target hooks to use unaligned load / stores. e.g. vld1.8 / vst1.8.
Also increase the threshold to something reasonable (8 for memset, 4 pairs
for memcpy).
This significantly improves Dhrystone, up to 50% on ARM iOS devices.
rdar://12760078
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169791 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/Mips/MipsISelLowering.cpp b/lib/Target/Mips/MipsISelLowering.cpp
index 703f8ce..619ae07 100644
--- a/lib/Target/Mips/MipsISelLowering.cpp
+++ b/lib/Target/Mips/MipsISelLowering.cpp
@@ -457,7 +457,8 @@
maxStoresPerMemcpy = 16;
}
-bool MipsTargetLowering::allowsUnalignedMemoryAccesses(EVT VT) const {
+bool
+MipsTargetLowering::allowsUnalignedMemoryAccesses(EVT VT, bool *Fast) const {
MVT::SimpleValueType SVT = VT.getSimpleVT().SimpleTy;
if (Subtarget->inMips16Mode())
@@ -466,6 +467,8 @@
switch (SVT) {
case MVT::i64:
case MVT::i32:
+ if (Fast)
+ *Fast = true;
return true;
default:
return false;