diff options
| -rw-r--r-- | llvm/lib/Target/X86/X86ISelDAGToDAG.cpp | 19 | ||||
| -rw-r--r-- | llvm/test/CodeGen/X86/narrow-shl-cst.ll | 2 |
2 files changed, 14 insertions, 7 deletions
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp index acd6e23a10c..fb48b087b41 100644 --- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp +++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp @@ -3586,16 +3586,23 @@ void X86DAGToDAGISel::Select(SDNode *Node) { // Check the minimum bitwidth for the new constant. // TODO: Using 16 and 8 bit operations is also possible for or32 & xor32. auto CanShrinkImmediate = [&](int64_t &ShiftedVal) { + if (Opcode == ISD::AND) { + // AND32ri is the same as AND64ri32 with zext imm. + // Try this before sign extended immediates below. + ShiftedVal = (uint64_t)Val >> ShAmt; + if (NVT == MVT::i64 && !isUInt<32>(Val) && isUInt<32>(ShiftedVal)) + return true; + } ShiftedVal = Val >> ShAmt; if ((!isInt<8>(Val) && isInt<8>(ShiftedVal)) || (!isInt<32>(Val) && isInt<32>(ShiftedVal))) return true; - // For 64-bit we can also try unsigned 32 bit immediates. - // AND32ri is the same as AND64ri32 with zext imm. - // MOV32ri+OR64r is cheaper than MOV64ri64+OR64rr - ShiftedVal = (uint64_t)Val >> ShAmt; - if (NVT == MVT::i64 && !isUInt<32>(Val) && isUInt<32>(ShiftedVal)) - return true; + if (Opcode != ISD::AND) { + // MOV32ri+OR64r/XOR64r is cheaper than MOV64ri64+OR64rr/XOR64rr + ShiftedVal = (uint64_t)Val >> ShAmt; + if (NVT == MVT::i64 && !isUInt<32>(Val) && isUInt<32>(ShiftedVal)) + return true; + } return false; }; diff --git a/llvm/test/CodeGen/X86/narrow-shl-cst.ll b/llvm/test/CodeGen/X86/narrow-shl-cst.ll index 3389ff731c9..0174803d449 100644 --- a/llvm/test/CodeGen/X86/narrow-shl-cst.ll +++ b/llvm/test/CodeGen/X86/narrow-shl-cst.ll @@ -66,7 +66,7 @@ define i64 @test6(i64 %x) nounwind { ; CHECK-LABEL: test6: ; CHECK: # %bb.0: ; CHECK-NEXT: movq %rdi, %rax -; CHECK-NEXT: andq $-65536, %rax # imm = 0xFFFF0000 +; CHECK-NEXT: andl $-65536, %eax # imm = 0xFFFF0000 ; CHECK-NEXT: shlq $32, %rax ; CHECK-NEXT: retq %and = shl i64 %x, 32 |
