[llvm] [LangRef] inline asm: the instructions are treated opaquely (PR #157080)

[Jacob Lifshay via llvm-commits]

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@@ -5229,6 +5229,11 @@ flag that indicates whether or not the inline asm expression has side effects,
 and a flag indicating whether the function containing the asm needs to align its
 stack conservatively.
 
+LLVM will treat the actual instructions entirely opaquely (i.e. no optimizations
+will be performed based on the contents of the template string). Only the flags,
+operand constraints, and attributes on the call and surrounding function are
+used to deduce what the expression may do during execution.
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programmerjake wrote:

iirc LLVM will sometimes reformat the asm string, so it's not strictly true that it's used verbatim.

https://github.com/llvm/llvm-project/pull/157080