[llvm] [CodeGen] [AMDGPU] Attempt DAGCombine for fmul with select to ldexp (PR #111109)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,2616 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+;RUN: llc -mtriple=amdgcn-amd-amdhsa -mcpu=gfx700 < %s | FileCheck -check-prefix=GFX7 %s
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arsenm wrote:

Should rebase on top of the test base. Patch lgtm with nit but I can't easily check the effect in the output here 

https://github.com/llvm/llvm-project/pull/111109