[PATCH] D92289: [RISCV] Only combine (or (GREVI x, shamt), x) -> GORCI if shamt is a power of 2.

[Craig Topper via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGcbbd7021f176: [RISCV] Only combine (or (GREVI x, shamt), x) -> GORCI if shamt is a power of 2. (authored by craig.topper).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D92289/new/

https://reviews.llvm.org/D92289

Files:
  llvm/lib/Target/RISCV/RISCVISelLowering.cpp


Index: llvm/lib/Target/RISCV/RISCVISelLowering.cpp
===================================================================
--- llvm/lib/Target/RISCV/RISCVISelLowering.cpp
+++ llvm/lib/Target/RISCV/RISCVISelLowering.cpp
@@ -1238,8 +1238,8 @@
 }
 
 // Matches any the following pattern as a GORCI(W) operation
-// 1.  (or (GREVI x, shamt), x)
-// 2.  (or x, (GREVI x, shamt))
+// 1.  (or (GREVI x, shamt), x) if shamt is a power of 2
+// 2.  (or x, (GREVI x, shamt)) if shamt is a power of 2
 // 3.  (or (or (BITMANIP_SHL x), x), (BITMANIP_SRL x))
 // Note that with the variant of 3.,
 //     (or (or (BITMANIP_SHL x), (BITMANIP_SRL x)), x)
@@ -1258,7 +1258,8 @@
     for (const auto &OpPair :
          {std::make_pair(Op0, Op1), std::make_pair(Op1, Op0)}) {
       if (OpPair.first.getOpcode() == RISCVISD::GREVI &&
-          OpPair.first.getOperand(0) == OpPair.second)
+          OpPair.first.getOperand(0) == OpPair.second &&
+          isPowerOf2_32(OpPair.first.getConstantOperandVal(1)))
         return DAG.getNode(RISCVISD::GORCI, DL, VT, OpPair.second,
                            OpPair.first.getOperand(1));
     }


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