[PATCH] D65448: [AArch64] Implement initial SVE calling convention support

[Oliver Stannard (Linaro) via Phabricator via llvm-commits]

ostannard added a comment.

Out of interest, why does the ABI allow functions which don't have SVE args/returns to clobber the P registers? For Z registers, we've got to be compatible with old code which only needed to save the bottom half of v8-v15, but there should be no existing code which uses P registers, so we could enforce a mixture of callee- and caller-saved P registers for all code. Existing code is already compliant with this, because it doesn't touch the P regs.



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Comment at: lib/Target/AArch64/AArch64ISelLowering.cpp:3968
 
+  // SVE mask....
+  if (CallConv == CallingConv::C) {
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Comments should be complete sentences.


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Comment at: test/CodeGen/AArch64/sve-calling-convention.ll:9
+; CHECK: name: sve_signature_vec
+; CHECK-DAG: [[RES:%[0-9]+]]:zpr = COPY $z1
+; CHECK-DAG: $z0 = COPY [[RES]]
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These must be in this order, so shouldn't be CHECK-DAG.


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Comment at: test/CodeGen/AArch64/sve-calling-convention.ll:32
+; CHECK: name: sve_signature_vec_caller
+; CHECK-DAG:  $z0 = COPY %1
+; CHECK-DAG:  $z1 = COPY %0
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These should use a regex for the vreg number on the right.


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Comment at: test/CodeGen/AArch64/sve-calling-convention.ll:34
+; CHECK-DAG:  $z1 = COPY %0
+; CHECK-NEXT: BL @sve_signature_vec, csr_aarch64_sve_aapcs
+; CHECK:      RET_ReallyLR implicit $z0
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Can we check that the return value is pulled out of the right register?


Repository:
  rL LLVM

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D65448/new/

https://reviews.llvm.org/D65448