[llvm] Adding support in llvm-exegesis for Aarch64 for handling FPR64/128, PPR16 and ZPR128 reg class. (PR #127564)

[via llvm-commits]

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@@ -28,13 +28,58 @@ static unsigned getLoadImmediateOpcode(unsigned RegBitWidth) {
 // Generates instruction to load an immediate value into a register.
 static MCInst loadImmediate(MCRegister Reg, unsigned RegBitWidth,
                             const APInt &Value) {
-  if (Value.getBitWidth() > RegBitWidth)
-    llvm_unreachable("Value must fit in the Register");
+  // 0 <= Value.getZExtValue() < 2**16
+  assert(Value.getZExtValue() < (1 << 16) &&
+         "Value must be in the range of the immediate opcode");
   return MCInstBuilder(getLoadImmediateOpcode(RegBitWidth))
       .addReg(Reg)
       .addImm(Value.getZExtValue());
 }
 
+static MCInst loadZPRImmediate(MCRegister Reg, unsigned RegBitWidth,
+                               const APInt &Value) {
+  // -127 <= Value.getZExtValue() < 128
+  assert(Value.getZExtValue() < (1 << 7) &&
+         "Value must be in the range of the immediate opcode");
+  return MCInstBuilder(AArch64::DUP_ZI_D)
+      .addReg(Reg)
+      .addImm(Value.getZExtValue())
+      .addImm(0);
+}
+
+static MCInst loadPPRImmediate(MCRegister Reg, unsigned RegBitWidth,
+                               const APInt &Value) {
+  // For PPR, we typically use PTRUE instruction to set predicate registers
+  return MCInstBuilder(AArch64::PTRUE_B)
+      .addReg(Reg)
+      .addImm(31); // All lanes true for 16 bits
+}
+
+// Fetch base-instruction to load an FP immediate value into a register.
+static unsigned getLoadFPImmediateOpcode(unsigned RegBitWidth) {
+  switch (RegBitWidth) {
+  case 64:
+    return AArch64::MOVID; //FMOVDi;
+  case 128:
+    return AArch64::MOVIv2d_ns;
+  }
+  llvm_unreachable("Invalid Value Width");
+}
+
+// Generates instruction to load an FP immediate value into a register.
+static MCInst loadFPImmediate(MCRegister Reg, unsigned RegBitWidth,
+                              const APInt &Value) {
+  // 0 <= Value.getZExtValue() < 2**8 (int Value)
+  // -31.0 <= Value.getZExtValue() < 31.0 (frac Value)
+  assert(Value.getZExtValue() == 0 &&
+         "Value should be zero, temporary fix for now");
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lakshayk-nv wrote:

Done.

https://github.com/llvm/llvm-project/pull/127564