[PATCH] D117927: [SystemZ] Don't shrink FP constants

[Jonas Paulsson via Phabricator via llvm-commits]

jonpa added inline comments.


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Comment at: llvm/test/CodeGen/SystemZ/call-zos-01.ll:169
+; CHECK: ld 1, 0(1)
+; CHECK: ld 3, 8(1)
 ; CHECK: axbr  0, 1
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uweigand wrote:
> Hmm.   For the 128-bit constant case, I think the `lxdb` remains preferable - this new version now has two instructions, which most likely will be worse.   So maybe in that case we still should try to shrink?
ok, now only doing the 64-bit case (which is a no-change on SPEC).

I tried compiling this function also for Z14, but the FP 128 constant was loaded with a VL just the same regardless of what this target hook returns... So instead of checking for vector-enhancements-1, just returning true always if not 64-bit.

The other benefit of having the full constant in memory would be to use reg/mem MXDB, but I think that would be unlikely to make much difference...


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https://reviews.llvm.org/D117927