Generating BZHI in the variable mask case, i.e. (and X, (sub (shl 1, N), 1)),
was already supported, but we were missing the constant-mask case. This patch
fixes that.
<rdar://problem/
15480077>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206738
91177308-0d34-0410-b5e6-
96231b3b80d8
}
} // BEXTR
+ // Check for BZHI with contiguous mask: (and X, 0x0..0f..f)
+ // This should be checked after BEXTR - when X is a shift, a BEXTR is
+ // preferrable.
+ if (Subtarget->hasBMI2()) {
+ if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(N1)) {
+ uint64_t Mask = C->getZExtValue();
+ if (isMask_64(Mask)) {
+ unsigned LZ = CountTrailingOnes_64(Mask);
+ return DAG.getNode(X86ISD::BZHI, DL, VT, N0,
+ DAG.getConstant(LZ, MVT::i8));
+ }
+ }
+ }
+
return SDValue();
}
; CHECK: bzhiq
}
+define i32 @bzhi32_constant_mask(i32 %x) #0 {
+entry:
+ %and = and i32 %x, 1073741823
+ ret i32 %and
+; CHECK-LABEL: bzhi32_constant_mask:
+; CHECK: movb $30, %al
+; CHECK: bzhil %eax, %edi, %eax
+}
+
+define i64 @bzhi64_constant_mask(i64 %x) #0 {
+entry:
+ %and = and i64 %x, 4611686018427387903
+ ret i64 %and
+; CHECK-LABEL: bzhi64_constant_mask:
+; CHECK: movb $62, %al
+; CHECK: bzhiq %rax, %rdi, %rax
+}
+
define i32 @blsi32(i32 %x) nounwind readnone {
%tmp = sub i32 0, %x
%tmp2 = and i32 %x, %tmp