[WebAssembly] Fold setne and seteq comparisons into selects.

[oota-llvm.git] / lib / Target / WebAssembly / WebAssemblyInstrInteger.td

diff --git a/lib/Target/WebAssembly/WebAssemblyInstrInteger.td b/lib/Target/WebAssembly/WebAssemblyInstrInteger.td
index bc00cd6b4f7f50944501fec8ce99418d767341c6..3fa2f712034ad0dc68f8726e4d33e7cd1f7dc983 100644 (file)
--- a/lib/Target/WebAssembly/WebAssemblyInstrInteger.td
+++ b/lib/Target/WebAssembly/WebAssemblyInstrInteger.td
@@ -63,3 +63,17 @@ def SELECT_I64 : I<(outs I64:$dst), (ins I32:$cond, I64:$lhs, I64:$rhs),
                    "i64.select\t$dst, $cond, $lhs, $rhs">;
 
 } // Defs = [ARGUMENTS]
+
+// ISD::SELECT requires its operand to conform to getBooleanContents, but
+// WebAssembly's select interprets any non-zero value as true, so we can fold
+// a setne with 0 into a select.
+def : Pat<(select (i32 (setne I32:$cond, 0)), I32:$lhs, I32:$rhs),
+          (SELECT_I32 I32:$cond, I32:$lhs, I32:$rhs)>;
+def : Pat<(select (i32 (setne I32:$cond, 0)), I64:$lhs, I64:$rhs),
+          (SELECT_I64 I32:$cond, I64:$lhs, I64:$rhs)>;
+
+// And again, this time with seteq instead of setne and the arms reversed.
+def : Pat<(select (i32 (seteq I32:$cond, 0)), I32:$lhs, I32:$rhs),
+          (SELECT_I32 I32:$cond, I32:$rhs, I32:$lhs)>;
+def : Pat<(select (i32 (seteq I32:$cond, 0)), I64:$lhs, I64:$rhs),
+          (SELECT_I64 I32:$cond, I64:$rhs, I64:$lhs)>;