[PATCH] D54770: [x86] try to lower multiply i8 with constant to LEA

[Craig Topper via Phabricator via llvm-commits]

craig.topper added inline comments.


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Comment at: lib/Target/X86/X86ISelLowering.cpp:23430
+        // Extend/truncate an 8-bit multiply to 32-bit to allow LEA formation.
+        SDValue ZextOp0 = DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i32, A);
+        SDValue NewMul = DAG.getNode(ISD::MUL, dl, MVT::i32, ZextOp0,
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Why ZERO_EXTEND and not ANY_EXTEND?


https://reviews.llvm.org/D54770