[PowerPC][NFC] Add new mtpidr alias introduced in ISA3.0

[lei137]

Add new alias m[tf]pidr for m[tf]spr 48 introduced in ISA3.0.

[llvmbot]

@llvm/pr-subscribers-backend-powerpc

Author: Lei Huang (lei137)

Changes

Add new alias m[tf]pidr for m[tf]spr 48 introduced in ISA3.0.

---

Full diff: https://github.com/llvm/llvm-project/pull/163989.diff

2 Files Affected:

• (modified) llvm/lib/Target/PowerPC/PPCInstrInfo.td (+2)
• (modified) llvm/test/MC/PowerPC/ppc64-encoding-ext.s (+10-4)

diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.td b/llvm/lib/Target/PowerPC/PPCInstrInfo.td
index aca7abd5a45a7..44d1a445f82be 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.td
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.td
@@ -4578,6 +4578,8 @@ def : InstAlias<"mfamr $Rx", (MFSPR gprc:$Rx, 29)>;
 
 def : InstAlias<"mtpid $Rx", (MTSPR 48, gprc:$Rx)>, Requires<[IsBookE]>;
 def : InstAlias<"mfpid $Rx", (MFSPR gprc:$Rx, 48)>, Requires<[IsBookE]>;
+def : InstAlias<"mtpidr $Rx", (MTSPR 48, gprc:$Rx)>, Requires<[IsISA3_0]>;
+def : InstAlias<"mfpidr $Rx", (MFSPR gprc:$Rx, 48)>, Requires<[IsISA3_0]>;
 
 foreach SPRG = 4-7 in {
   def : InstAlias<"mfsprg $RT, "#SPRG, (MFSPR gprc:$RT, !add(SPRG, 256))>,
diff --git a/llvm/test/MC/PowerPC/ppc64-encoding-ext.s b/llvm/test/MC/PowerPC/ppc64-encoding-ext.s
index 959f3c53b0a19..666222028bdf8 100644
--- a/llvm/test/MC/PowerPC/ppc64-encoding-ext.s
+++ b/llvm/test/MC/PowerPC/ppc64-encoding-ext.s
@@ -3491,12 +3491,18 @@
 # CHECK-BE: mfamr 2                         # encoding: [0x7c,0x5d,0x02,0xa6]
 # CHECK-LE: mfamr 2                         # encoding: [0xa6,0x02,0x5d,0x7c]
             mfamr 2
-# CHECK-BE: mtpid 2                         # encoding: [0x7c,0x50,0x0b,0xa6]
-# CHECK-LE: mtpid 2                         # encoding: [0xa6,0x0b,0x50,0x7c]
+# CHECK-BE: mtspr 48, 2                     # encoding: [0x7c,0x50,0x0b,0xa6]
+# CHECK-LE: mtspr 48, 2                     # encoding: [0xa6,0x0b,0x50,0x7c]
             mtpid 2
-# CHECK-BE: mfpid 2                         # encoding: [0x7c,0x50,0x0a,0xa6]
-# CHECK-LE: mfpid 2                         # encoding: [0xa6,0x0a,0x50,0x7c]
+# CHECK-BE: mtspr 48, 2                     # encoding: [0x7c,0x50,0x0b,0xa6]
+# CHECK-LE: mtspr 48, 2                     # encoding: [0xa6,0x0b,0x50,0x7c]
+            mtpidr 2
+# CHECK-BE: mfspr 2, 48                     # encoding: [0x7c,0x50,0x0a,0xa6]
+# CHECK-LE: mfspr 2, 48                     # encoding: [0xa6,0x0a,0x50,0x7c]
             mfpid 2
+# CHECK-BE: mfspr 2, 48                     # encoding: [0x7c,0x50,0x0a,0xa6]
+# CHECK-LE: mfspr 2, 48                     # encoding: [0xa6,0x0a,0x50,0x7c]
+            mfpidr 2
 # CHECK-BE: mtlr 2                          # encoding: [0x7c,0x48,0x03,0xa6]
 # CHECK-LE: mtlr 2                          # encoding: [0xa6,0x03,0x48,0x7c]
             mtlr 2

[lei137]

Reference: When multiple aliases are added for the same encoding, compiler doesn't know which one to chose so default to the original instruction vs the alias instr name. Thus the encoding test for mtpid|mtpidr both results in the mtspr 48 instruction. However both forms are recognized as valid instructions.