[llvm] [SPIR-V] Fix environment resolution causing legalization crash (PR #179052)

[Steven Perron via llvm-commits]

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@@ -173,6 +173,25 @@ void SPIRVSubtarget::initAvailableExtInstSets() {
   accountForAMDShaderTrinaryMinmax();
 }
 
+void SPIRVSubtarget::resolveEnvFromModule(const Module &M) {
+  if (Env != Unknown)
+    return;
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s-perron wrote:

Do we care about the case where the same instance of the backend is used to compile multiple modules that may have different ENVs? I think it is safe to fail in that case because that is generally not supported by an LLVM module anyway. I just want to be sure we make an explicit decision.

https://github.com/llvm/llvm-project/pull/179052