[PATCH] D107650: GlobalISel[RFC]: Avoid use of G_INSERT and G_EXTRACT in Legalizer

[Amara Emerson via Phabricator via llvm-commits]

aemerson added a comment.

Haven't finished grokking this yet, some comments so far.



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Comment at: llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h:501
+  /// Build and insert a, b, ..., x = G_UNMERGE_VALUES \p Op0
+  /// Build and insert \p Res = G_BUILD_VECTOR a, b, ..., x, undef, ..., undef
+  ///
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Comment at: llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h:514
+  /// Build and insert a, b, ..., x, y, z = G_UNMERGE_VALUES \p Op0
+  /// Build and insert \p Res = G_BUILD_VECTOR a, b, ..., x
+  ///
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ditto


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Comment at: llvm/lib/CodeGen/GlobalISel/Legalizer.cpp:229-234
+    ++IterCount;
+    if (IterCount == 1000) {
+      llvm_unreachable(("infinite loop in " + MF.getName().str() +
+                        " , TODO: fix mir tests\n\n")
+                           .c_str());
+    }
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?


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Comment at: llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp:2876
 
+  if (MemTy.isVector() && DstTy.isVector()) {
+    LLT EltTy = MemTy.getScalarType();
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Why is this code needed? Can this be a follow up change?


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  https://reviews.llvm.org/D107650/new/

https://reviews.llvm.org/D107650