[llvm] [AMDGPU] Eliminate likely-spurious execz checks via intrinsic argument (PR #123749)

[Matt Arsenault via llvm-commits]

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@@ -417,8 +417,8 @@ def IGLP_OPT : SPseudoInstSI<(outs), (ins i32imm:$mask),
 let isTerminator = 1, isNotDuplicable = 1 in {
 
 def SI_IF: CFPseudoInstSI <
-  (outs SReg_1:$dst), (ins SReg_1:$vcc, brtarget:$target),
-  [(set i1:$dst, (AMDGPUif i1:$vcc, bb:$target))], 1, 1> {
+  (outs SReg_1:$dst), (ins SReg_1:$vcc, i1imm:$likelyvarying, brtarget:$target),
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arsenm wrote:

Also rename here 

https://github.com/llvm/llvm-project/pull/123749