[PATCH] D72189: [SystemZ] Support -msoft-float

[Jonas Paulsson via Phabricator via llvm-commits]

jonpa updated this revision to Diff 241792.
jonpa marked 6 inline comments as done.
jonpa added a comment.

> If soft-float, then we have *no* VectorABI!

Oh! I misunderstood your previous comment "with -msoft-float, GCC also falls back to the 16-byte vector alignment, so we must match that for ABI compatibility" to mean that (source code) vectors should be aligned to 16 bytes in memory. I also think I saw GCC outputing an NLL to align a store in such a case, but I can't reproduce so I guess I was confused.

> What's the difference in assembler? Could this be because you've implemented the VectorABI check the wrong way around? (If soft-float, then we have *no* VectorABI!)

Also with the latest updates of the patch, I see for this function:

  typedef int v4si __attribute__ ((vector_size (16)));
  v4si foo(v4si *Dst) {
    return *Dst;
  }



  gcc -S -O3 -march=z14 -msoft-float
  
  foo:
    lmg     %r4,%r5,0(%r3)
    stmg    %r4,%r5,0(%r2)
    br      %r14



  clang -S -O3 -march=z14 -msoft-float
  
  foo:                                    # @foo
  l       %r0, 0(%r2)
  l       %r3, 4(%r2)
  l       %r4, 8(%r2)
  l       %r5, 12(%r2)
  lr      %r2, %r0
  br      %r14

It seems that gcc is loading from %r3, while clang is loading from %r2, and gcc is returning on the stack, while clang seems to be returning in registers.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D72189/new/

https://reviews.llvm.org/D72189

Files:
  clang/lib/Basic/Targets/SystemZ.h
  clang/lib/CodeGen/TargetInfo.cpp
  clang/lib/Driver/ToolChains/Arch/SystemZ.cpp
  clang/lib/Driver/ToolChains/Arch/SystemZ.h
  clang/lib/Driver/ToolChains/Clang.cpp
  clang/test/CodeGen/systemz-abi.c
  clang/test/CodeGen/systemz-abi.cpp
  clang/test/CodeGen/target-data.c
  clang/test/Driver/systemz-float-01.c
  clang/test/Driver/systemz-float-02.c
  llvm/lib/Target/SystemZ/SystemZFeatures.td
  llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
  llvm/lib/Target/SystemZ/SystemZISelLowering.h
  llvm/lib/Target/SystemZ/SystemZSubtarget.cpp
  llvm/lib/Target/SystemZ/SystemZSubtarget.h
  llvm/lib/Target/SystemZ/SystemZTargetMachine.cpp
  llvm/test/CodeGen/SystemZ/args-07.ll
  llvm/test/CodeGen/SystemZ/soft-float-01.ll
  llvm/test/CodeGen/SystemZ/soft-float-02.ll
  llvm/test/CodeGen/SystemZ/soft-float-03.ll
  llvm/test/CodeGen/SystemZ/soft-float-04.ll
  llvm/test/CodeGen/SystemZ/soft-float-args.ll
  llvm/test/CodeGen/SystemZ/soft-float-inline-asm-01.ll
  llvm/test/CodeGen/SystemZ/soft-float-inline-asm-02.ll
  llvm/test/CodeGen/SystemZ/soft-float-inline-asm-03.ll
  llvm/test/CodeGen/SystemZ/vec-abi-align.ll
  llvm/test/CodeGen/SystemZ/vec-args-06.ll
  llvm/test/CodeGen/SystemZ/vec-args-07.ll

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