[PATCH] D90091: [SelectionDAGBuilder] Let asm constraint "i" accept an undef operand.

[Nick Desaulniers via Phabricator via llvm-commits]

nickdesaulniers requested changes to this revision.
nickdesaulniers added a comment.
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Interesting, did this come from actual C code?  It looks to me like GCC and Clang both currently reject such input:

  int foo(void) {
      int x;
      asm volatile (""::"i"(x));
      return x;
  }

Why should we allow that? Seems more indicative of a bug in the source code?  Or do you have a different test case that more clearly illuminates the issue in LLVM?



================
Comment at: llvm/test/CodeGen/SystemZ/asm-20.ll:3
 
+; Test that asm goto can be compiled.
 define i32 @c() {
----------------
Probably don't need to reorder these?


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https://reviews.llvm.org/D90091