[PATCH] D62966: [ARM] Add fp16 addressing to isLegalT2AddressImmediate

[Dave Green via Phabricator via llvm-commits]

dmgreen created this revision.
dmgreen added reviewers: SjoerdMeijer, t.p.northover, samparker, simon_tatham.
Herald added subscribers: hiraditya, kristof.beyls, javed.absar.
Herald added a project: LLVM.

The fp16 version of VLDR takes a imm8 multiplied by 2. This updates the costs to account for those, and adds extra testing (which I've just shown the diff of here). It is dependant upon hasFPRegs16 as this is what the load/store instructions require.


https://reviews.llvm.org/D62966

Files:
  llvm/lib/Target/ARM/ARMISelLowering.cpp
  llvm/test/Analysis/CostModel/ARM/gep.ll


Index: llvm/test/Analysis/CostModel/ARM/gep.ll
===================================================================
--- llvm/test/Analysis/CostModel/ARM/gep.ll
+++ llvm/test/Analysis/CostModel/ARM/gep.ll
@@ -322,15 +322,15 @@
 ;
 ; CHECK-MVE-LABEL: 'testhalf'
 ; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a0 = getelementptr inbounds half, half* %a, i32 0
-; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %a1 = getelementptr inbounds half, half* %a, i32 1
-; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %am1 = getelementptr inbounds half, half* %a, i32 -1
-; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %a255 = getelementptr inbounds half, half* %a, i32 255
-; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a256 = getelementptr inbounds half, half* %a, i32 256
-; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %am255 = getelementptr inbounds half, half* %a, i32 -255
-; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %am256 = getelementptr inbounds half, half* %a, i32 -256
+; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a1 = getelementptr inbounds half, half* %a, i32 1
+; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %am1 = getelementptr inbounds half, half* %a, i32 -1
+; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %a255 = getelementptr inbounds half, half* %a, i32 255
+; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %a256 = getelementptr inbounds half, half* %a, i32 256
+; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %am255 = getelementptr inbounds half, half* %a, i32 -255
+; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %am256 = getelementptr inbounds half, half* %a, i32 -256
 ; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %a1023 = getelementptr inbounds half, half* %a, i32 1023
 ; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %a1024 = getelementptr inbounds half, half* %a, i32 1024
-; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %am63 = getelementptr inbounds half, half* %a, i32 -63
+; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %am63 = getelementptr inbounds half, half* %a, i32 -63
 ; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: %am64 = getelementptr inbounds half, half* %a, i32 -64
 ; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %ai = getelementptr inbounds half, half* %a, i32 %i
 ; CHECK-MVE-NEXT:  Cost Model: Found an estimated cost of 0 for instruction: ret void
Index: llvm/lib/Target/ARM/ARMISelLowering.cpp
===================================================================
--- llvm/lib/Target/ARM/ARMISelLowering.cpp
+++ llvm/lib/Target/ARM/ARMISelLowering.cpp
@@ -13300,6 +13300,9 @@
 
   unsigned NumBytes = std::max(VT.getSizeInBits() / 8, 1U);
 
+  // half VLDR: 2 * imm8
+  if (VT.isFloatingPoint() && NumBytes == 2 && Subtarget->hasFPRegs16())
+    return isShiftedUInt<8, 1>(V);
   // VLDR and LDRD: 4 * imm8
   if ((VT.isFloatingPoint() && Subtarget->hasVFP2Base()) || NumBytes == 8)
     return isShiftedUInt<8, 2>(V);


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