[llvm] [AMDGPU] Prevent folding of FMAC into FMAAK with two literals (PR #217438)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,20 @@
+# RUN: llc -mtriple=amdgcn -mcpu=gfx1201 -run-pass peephole-opt -verify-machineinstrs -o - %s | FileCheck %s
+
+# An FMAC whose src1 is already a literal must not be folded into FMAAK as VOP2/VOP3
+# instruction cannot uses more than one literal.
+
+---
----------------
arsenm wrote:

Can you merge this into an existing test for these folds 

https://github.com/llvm/llvm-project/pull/217438