[PATCH] D50986: [ShrinkWrap] Don't put pseudo-instrs which use $sp before prologue setup

[Vladimir Stefanovic via Phabricator via llvm-commits]

vstefanovic added a comment.

Thanks for the comments, adding $sp as implicit operand is a lot better, no need to modify ShrinkWrapping then.

An example - BuildPair64 loads 64 bits into a FPR from two GPRs.

  $d0 = BuildPairF64 $zero, $zero

This is later usually expanded to mtc1 + mthc1:

  $f0 = MTC1 $zero
  $d0 = MTHC1_D32 $d0, $zero

but when mthc1 isn't available (e.g. for '-mfpxx -mcpu=mips32'), $d0 is loaded via stack:

  SW $zero, $sp, 16
  SW $zero, $sp, 20
  $d0 = LDC1 $sp, 16

(I'll update commit message if this is ok.)



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Comment at: test/CodeGen/Mips/shrink-wrap-buildpairf64-extractelementf64.ll:1
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+
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thegameg wrote:
> Can you please add a MIR test with `-start-before shrink-wrap -stop-after prologepilog` instead of an IR test?
I also need to check whether $sp is added to implicit operands in the isel pass.
There could be a separate test for that, but I found it more convenient to cover everything with one input.


Repository:
  rL LLVM

https://reviews.llvm.org/D50986