Remove ninf which is not needed.

Author: Xiang Li

mlir/lib/Dialect/Arith/IR/ArithOps.cpp

@@ -1282,10 +1282,8 @@ OpFoldResult arith::MulFOp::fold(FoldAdaptor adaptor) {
   if (matchPattern(adaptor.getRhs(), m_OneFloat()))
     return getLhs();
 
-  arith::FastMathFlags fmf = getFastmath();
-  if (arith::bitEnumContainsAll(fmf, arith::FastMathFlags::nnan |
-                                         arith::FastMathFlags::ninf |
-                                         arith::FastMathFlags::nsz)) {
+  if (arith::bitEnumContainsAll(getFastmath(), arith::FastMathFlags::nnan |
+                                                   arith::FastMathFlags::nsz)) {
     // mulf(x, 0) -> 0
     if (matchPattern(adaptor.getRhs(), m_AnyZeroFloat()))
       return getRhs();

mlir/test/Dialect/Arith/canonicalize.mlir

@@ -2221,7 +2221,7 @@ func.func @test_mulf2(%arg0 : f32) -> f32 {
   // CHECK-NEXT:  %[[C0:.+]] = arith.constant 0.000000e+00 : f32
   // CHECK-NEXT:  return %[[C0]]
   %c0 = arith.constant 0.0 : f32
-  %0 = arith.mulf %c0, %arg0 fastmath<nnan,ninf,nsz> : f32
+  %0 = arith.mulf %c0, %arg0 fastmath<nnan,nsz> : f32
   return %0 : f32
 }