llvm/lib
Duncan P. N. Exon Smith 698c0a7097 ValueMapper: Treat LocalAsMetadata more like function-local Values
This is a partial re-commit -- maybe more of a re-implementation -- of
r265631 (reverted in r265637).

This makes RF_IgnoreMissingLocals behave (almost) consistently between
the Value and the Metadata hierarchy.  In particular:

  - MapValue returns nullptr or "metadata !{}" for missing locals in
    MetadataAsValue/LocalAsMetadata bridging paris, depending on
    the RF_IgnoreMissingLocals flag.

  - MapValue doesn't memoize LocalAsMetadata-related results.

  - MapMetadata no longer deals with LocalAsMetadata or
    RF_IgnoreMissingLocals at all.  (This wasn't in r265631 at all, but
    I realized during testing it would make the patch simpler with no
    loss of generality.)

r265631 went too far, making both functions universally ignore
RF_IgnoreMissingLocals.  This broke building (e.g.) compiler-rt.
Reassociate (and possibly other passes) don't currently maintain
dominates-use invariants for metadata operands, resulting in IR like
this:

    define void @foo(i32 %arg) {
      call void @llvm.some.intrinsic(metadata i32 %x)
      %x = add i32 1, i32 %arg
    }

If the inliner chooses to inline @foo into another function, then
RemapInstruction will call `MapValue(metadata i32 %x)` and assert that
the return is not nullptr.

I've filed PR27273 to add a Verifier check and fix the underlying
problem in the optimization passes.

As a workaround, return `!{}` instead of nullptr for unmapped
LocalAsMetadata when RF_IgnoreMissingLocals is unset.  Otherwise, match
the behaviour of r265631.

Original commit message:

    ValueMapper: Make LocalAsMetadata match function-local Values

    Start treating LocalAsMetadata similarly to function-local members of
    the Value hierarchy in MapValue and MapMetadata.

      - Don't memoize them.
      - Return nullptr if they are missing.

    This also cleans up ConstantAsMetadata to stop listening to the
    RF_IgnoreMissingLocals flag.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@265759 91177308-0d34-0410-b5e6-96231b3b80d8
2016-04-08 00:33:44 +00:00
..
Analysis Const correctness for BranchProbabilityInfo (NFC) 2016-04-07 21:59:28 +00:00
AsmParser [GCC] Attribute ifunc support in llvm 2016-04-07 12:32:19 +00:00
Bitcode Rename parameter I to Index for WriteCombinedGlobalValueSummary() (NFC) 2016-04-07 21:49:31 +00:00
CodeGen Revert "[TargetRegisterInfo] Refactor the code to use BitMaskClassIterator." 2016-04-08 00:03:51 +00:00
DebugInfo Thread Expected<...> up from createMachOObjectFile() to allow llvm-objdump to produce a real error message 2016-04-06 22:14:09 +00:00
ExecutionEngine Thread Expected<...> up from createMachOObjectFile() to allow llvm-objdump to produce a real error message 2016-04-06 22:14:09 +00:00
Fuzzer [libfuzzer] adding license headers to cpp files 2016-04-01 18:38:58 +00:00
IR ValueMapper: Treat LocalAsMetadata more like function-local Values 2016-04-08 00:33:44 +00:00
IRReader Remove autoconf support 2016-01-26 21:29:08 +00:00
LibDriver Remove autoconf support 2016-01-26 21:29:08 +00:00
LineEditor Fix Clang-tidy modernize-deprecated-headers warnings in some files; other minor fixes. 2016-03-28 17:40:08 +00:00
Linker IR: RF_IgnoreMissingValues => RF_IgnoreMissingLocals, NFC 2016-04-07 00:26:43 +00:00
LTO [gold] Save bitcode for module partitions (save-temps + split codegen). 2016-04-06 18:32:13 +00:00
MC Handle section vs global name conflict. 2016-03-28 20:36:28 +00:00
Object Thread Expected<...> up from createMachOObjectFile() to allow llvm-objdump to produce a real error message 2016-04-06 22:14:09 +00:00
ObjectYAML [lanai] Add Lanai backend. 2016-03-28 13:09:54 +00:00
Option Annotate dump() methods with LLVM_DUMP_METHOD, addressing Richard Smith r259192 post commit comment. 2016-01-29 20:50:44 +00:00
Passes [PM] Rename the CRTP mixin base classes for the new pass manager to 2016-03-11 10:33:22 +00:00
ProfileData Thread Expected<...> up from createMachOObjectFile() to allow llvm-objdump to produce a real error message 2016-04-06 22:14:09 +00:00
Support Fix a race condition in support library ThreadPool. 2016-04-06 23:46:40 +00:00
TableGen [TableGen] Fix typos in comments. NFC 2016-02-26 06:50:27 +00:00
Target [AArch64] Fix a typo in the register class to register bank mapping. 2016-04-07 23:10:14 +00:00
Transforms ValueMapper: Treat LocalAsMetadata more like function-local Values 2016-04-08 00:33:44 +00:00
CMakeLists.txt Move ObjectYAML code to a new library. 2016-03-01 19:15:06 +00:00
LLVMBuild.txt Add LLVMBuild for ObjectYAML. 2016-03-01 21:29:33 +00:00