[clang] [HLSL] Use icmp ne instead of trunc on boolean load (PR #221105)

[via cfe-commits]

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@@ -0,0 +1,3 @@
+// RUN: %clang_dxc -T cs_6_3 -### %s 2>&1 | FileCheck %s
+
+// CHECK: "-load-bool-from-mem=nonzero"
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joaosaffran wrote:

I think we could add a few more tests:
- A `%clang_cc1` invocation test without `-load-bool-from-mem`, checking that scalar and vector boolean loads use nonzero comparisons rather than truncation. 
- A test with `-load-bool-from-mem=truncate`, checking that the warning is being emitted and the codegen is still correct.
- The issue being fixed has a godbolt link; it is nice to add that as a regression test

https://github.com/llvm/llvm-project/pull/221105