Simplify EmitZaInstr with StartIdx

Author: CarolineConcatto

clang/test/CodeGen/aarch64-sme2p1-intrinsics/acle_sme2p1_movaz.c

@@ -1,6 +1,6 @@
 // NOTE: Assertions have been autogenerated by utils/update_cc_test_checks.py UTC_ARGS: --version 4
- //RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme2p1 -target-feature +bf16 -S -disable-O0-optnone -Werror -Wall -emit-llvm -o - %s | opt -S -p mem2reg,instcombine,tailcallelim | FileCheck %s
-// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme2p1 -target-feature +bf16 -S -disable-O0-optnone -Werror -Wall -emit-llvm -o - -x c++ %s | opt -S -p mem2reg,instcombine,tailcallelim | FileCheck %s -check-prefix=CPP-CHECK
+ //RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme2p1 -target-feature +bf16 -disable-O0-optnone -Werror -Wall -emit-llvm -o - %s | opt -S -p mem2reg,instcombine,tailcallelim | FileCheck %s
+// RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme2p1 -target-feature +bf16 -disable-O0-optnone -Werror -Wall -emit-llvm -o - -x c++ %s | opt -S -p mem2reg,instcombine,tailcallelim | FileCheck %s -check-prefix=CPP-CHECK
 // RUN: %clang_cc1 -triple aarch64-none-linux-gnu -target-feature +sme2p1 -target-feature +bf16 -S -disable-O0-optnone -Werror -Wall -o /dev/null %s
 
 #include <arm_sme.h>

llvm/lib/Target/AArch64/AArch64ISelLowering.cpp

@@ -2958,17 +2958,15 @@ AArch64TargetLowering::EmitZAInstr(unsigned Opc, unsigned BaseReg,
   bool HasZPROut = HasTile && MI.getOperand(0).isReg();
   if (HasZPROut) {
     MIB.add(MI.getOperand(0)); // Output ZPR
-    MIB.addReg(BaseReg + MI.getOperand(1).getImm(),
-               RegState::Define);                    // Output ZA Tile
-    MIB.addReg(BaseReg + MI.getOperand(1).getImm()); // Input Za Tile
-    StartIdx = 2;
+    ++StartIdx;
+  }
+  if (HasTile) {
+    MIB.addReg(BaseReg + MI.getOperand(StartIdx).getImm(),
+               RegState::Define);                           // Output ZA Tile
+    MIB.addReg(BaseReg + MI.getOperand(StartIdx).getImm()); // Input Za Tile
+    StartIdx++;
   } else {
-    if (HasTile) {
-      MIB.addReg(BaseReg + MI.getOperand(0).getImm(), RegState::Define);
-      MIB.addReg(BaseReg + MI.getOperand(0).getImm());
-      StartIdx = 1;
-    } else
-      MIB.addReg(BaseReg, RegState::Define).addReg(BaseReg);
+    MIB.addReg(BaseReg, RegState::Define).addReg(BaseReg);
   }
   for (unsigned I = StartIdx; I < MI.getNumOperands(); ++I)
     MIB.add(MI.getOperand(I));
@@ -3009,7 +3007,6 @@ MachineBasicBlock *AArch64TargetLowering::EmitInstrWithCustomInserter(
       return EmitZAInstr(SMEOrigInstr, AArch64::ZAB0, MI, BB);
     case (AArch64::SMEMatrixTileH):
       return EmitZAInstr(SMEOrigInstr, AArch64::ZAH0, MI, BB);
-      ///*HasTile*/ true, /*HasZPROut*/ false);
     case (AArch64::SMEMatrixTileS):
       return EmitZAInstr(SMEOrigInstr, AArch64::ZAS0, MI, BB);
     case (AArch64::SMEMatrixTileD):