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llvm-mirror/lib/AsmParser
Sanjay Patel a3e1aa37c2 [IR] allow fast-math-flags on phi of FP values (2nd try)
The changes here are based on the corresponding diffs for allowing FMF on 'select':
D61917 <https://reviews.llvm.org/D61917>

As discussed there, we want to have fast-math-flags be a property of an FP value
because the alternative (having them on things like fcmp) leads to logical
inconsistency such as:
https://bugs.llvm.org/show_bug.cgi?id=38086

The earlier patch for select made almost no practical difference because most
unoptimized conditional code begins life as a phi (based on what I see in clang).
Similarly, I don't expect this patch to do much on its own either because
SimplifyCFG promptly drops the flags when converting to select on a minimal
example like:
https://bugs.llvm.org/show_bug.cgi?id=39535

But once we have this plumbing in place, we should be able to wire up the FMF
propagation and start solving cases like that.

The change to RecurrenceDescriptor::AddReductionVar() is required to prevent a
regression in a LoopVectorize test. We are intersecting the FMF of any
FPMathOperator there, so if a phi is not properly annotated, new math
instructions may not be either. Once we fix the propagation in SimplifyCFG, it
may be safe to remove that hack.

Differential Revision: https://reviews.llvm.org/D67564

llvm-svn: 372878
2019-09-25 14:35:02 +00:00
..
CMakeLists.txt
LLLexer.cpp
LLLexer.h
LLParser.cpp [IR] allow fast-math-flags on phi of FP values (2nd try) 2019-09-25 14:35:02 +00:00
LLParser.h
LLToken.h
LLVMBuild.txt
Parser.cpp [llvm] Migrate llvm::make_unique to std::make_unique 2019-08-15 15:54:37 +00:00