[llvm] [PowerPC][NFC] Add new mtpidr alias introduced in ISA3.0 (PR #163989)

[Lei Huang via llvm-commits]

https://github.com/lei137 created https://github.com/llvm/llvm-project/pull/163989

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

>From 6024fb90fb16e49fab3324e7414eea9c8d110098 Mon Sep 17 00:00:00 2001
From: Lei Huang <lei at ca.ibm.com>
Date: Fri, 17 Oct 2025 16:12:22 +0000
Subject: [PATCH] [PowerPC][NFC] Add new mtpidr alias introduced in ISA3.0

Add new alias `m[tf]pidr` for `m[tf]spr 48` introduced in ISA3.0.
---
 llvm/lib/Target/PowerPC/PPCInstrInfo.td   |  2 ++
 llvm/test/MC/PowerPC/ppc64-encoding-ext.s | 14 ++++++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

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