[PATCH] D143191: DAG: Handle inversion of fcSubnormal | fcZero

[Serge Pavlov via Phabricator via llvm-commits]

sepavloff added inline comments.


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Comment at: llvm/include/llvm/CodeGen/CodeGenCommonISel.h:223-224
+/// (i.e. fewer instructions should be required to lower it).  An example is the
+/// test "inf|normal|subnormal|zero", which is an inversion of "nan".  \param
+/// Test The test as specified in 'is_fpclass' intrinsic invocation.  \returns
+/// The inverted test, or fcNone, if inversion does not produce a simpler test.
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Doxygen comments must be on separate lines.


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Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:7333
   // TODO: Try getInvertedFPClassTest
+  bool IsInverted = false;
 
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This variable seems unused. It is possible to remove it?


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Comment at: llvm/test/CodeGen/X86/is_fpclass.ll:894-901
+; CHECK-32-NEXT:    flds {{[0-9]+}}(%esp)
+; CHECK-32-NEXT:    fldz
+; CHECK-32-NEXT:    fucompp
+; CHECK-32-NEXT:    fnstsw %ax
+; CHECK-32-NEXT:    # kill: def $ah killed $ah killed $ax
+; CHECK-32-NEXT:    sahf
+; CHECK-32-NEXT:    setp %cl
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This code looks incorrect. The argument is compared against 0.0 and the result is true if the comparison is unordered or not equal.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D143191/new/

https://reviews.llvm.org/D143191