[llvm] [AMDGPU] Rewrite `getVOP3DPPSrcForVT` with `!cond` (PR #81889)

[Shilei Tian via llvm-commits]

https://github.com/shiltian created https://github.com/llvm/llvm-project/pull/81889

`!cond` is much more clear than nested `!if`.


>From 936ccb90785e2375f129173fb79c128fbe8c8470 Mon Sep 17 00:00:00 2001
From: Shilei Tian <i at tianshilei.me>
Date: Thu, 15 Feb 2024 12:51:36 -0500
Subject: [PATCH] [AMDGPU] Rewrite `getVOP3DPPSrcForVT` with `!cond`

`!cond` is much more clear than nested `!if`.
---
 llvm/lib/Target/AMDGPU/SIInstrInfo.td | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/llvm/lib/Target/AMDGPU/SIInstrInfo.td b/llvm/lib/Target/AMDGPU/SIInstrInfo.td
index 2b47686f23c238..4b7555de712c80 100644
--- a/llvm/lib/Target/AMDGPU/SIInstrInfo.td
+++ b/llvm/lib/Target/AMDGPU/SIInstrInfo.td
@@ -1571,13 +1571,15 @@ class getVOP3SrcForVT<ValueType VT, bit IsTrue16 = 0> {
 // Src2 of VOP3 DPP instructions cannot be a literal
 class getVOP3DPPSrcForVT<ValueType VT> {
   RegisterOperand ret =
-      !if (!eq(VT.Value, i1.Value), SSrc_i1,
-           !if (VT.isFP,
-                !if (!or(!eq(VT.Value, f16.Value), !eq(VT.Value, bf16.Value)), VCSrc_f16,
-                     !if (!or(!eq(VT.Value, v2f16.Value), !eq(VT.Value, v2bf16.Value)), VCSrc_v2f16, VCSrc_f32)),
-                !if (!eq(VT.Value, i16.Value), VCSrc_b16,
-                     !if (!eq(VT.Value, v2i16.Value), VCSrc_v2b16,
-                          VCSrc_b32))));
+  !cond(!eq(VT, i1)     : SSrc_i1,
+        !eq(VT, i16)    : VCSrc_b16,
+        !eq(VT, f16)    : VCSrc_f16,
+        !eq(VT, bf16)   : VCSrc_f16,
+        !eq(VT, v2i16)  : VCSrc_v2b16,
+        !eq(VT, v2f16)  : VCSrc_v2f16,
+        !eq(VT, v2bf16) : VCSrc_v2f16,
+        !eq(VT, f32)    : VCSrc_f32,
+        1               : VCSrc_b32);
 }
 
 // Float or packed int