When merging Thumb2 loads/stores, do not give up when the offset is one of
the special values that for ARM would be used with IB or DA modes. Fall
through and consider materializing a new base address is it would be
profitable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112329 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMLoadStoreOptimizer.cpp b/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
index 4fff738..46254fd 100644
--- a/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
+++ b/lib/Target/ARM/ARMLoadStoreOptimizer.cpp
@@ -193,20 +193,17 @@
return false;
ARM_AM::AMSubMode Mode = ARM_AM::ia;
+ // VFP and Thumb2 do not support IB or DA modes.
bool isNotVFP = isi32Load(Opcode) || isi32Store(Opcode);
- if (isNotVFP && Offset == 4) {
- if (isThumb2)
- // Thumb2 does not support ldmib / stmib.
- return false;
+ bool haveIBAndDA = isNotVFP && !isThumb2;
+ if (Offset == 4 && haveIBAndDA)
Mode = ARM_AM::ib;
- } else if (isNotVFP && Offset == -4 * (int)NumRegs + 4) {
- if (isThumb2)
- // Thumb2 does not support ldmda / stmda.
- return false;
+ else if (Offset == -4 * (int)NumRegs + 4 && haveIBAndDA)
Mode = ARM_AM::da;
- } else if (isNotVFP && Offset == -4 * (int)NumRegs) {
+ else if (Offset == -4 * (int)NumRegs && isNotVFP)
+ // VLDM/VSTM do not support DB mode without also updating the base reg.
Mode = ARM_AM::db;
- } else if (Offset != 0) {
+ else if (Offset != 0) {
// If starting offset isn't zero, insert a MI to materialize a new base.
// But only do so if it is cost effective, i.e. merging more than two
// loads / stores.