[llvm] [WebAssembly] [Codegen] Add pattern for relaxed min max from pmin/pmax-based patterns over v4f32 and v2f64 (PR #164486)

[Jasmine Tang via llvm-commits]

================
@@ -1692,6 +1692,42 @@ defm SIMD_RELAXED_FMIN :
 defm SIMD_RELAXED_FMAX :
    RelaxedBinary<F64x2, int_wasm_relaxed_max, "relaxed_max", 0x110>;
 
+let Predicates = [HasRelaxedSIMD] in {
+  foreach vec = [F32x4, F64x2] in {
+    defvar relaxed_min = !cast<NI>("SIMD_RELAXED_FMIN_"#vec);
+    defvar relaxed_max = !cast<NI>("SIMD_RELAXED_FMAX_"#vec);
+
+    // Transform standard fminimum/fmaximum to relaxed versions
+    def : Pat<(vec.vt (fminnum (vec.vt V128:$lhs), (vec.vt V128:$rhs))),
+              (relaxed_min V128:$lhs, V128:$rhs)>;
+    def : Pat<(vec.vt (fminimumnum (vec.vt V128:$lhs), (vec.vt V128:$rhs))),
+              (relaxed_min V128:$lhs, V128:$rhs)>;
+    def : Pat<(vec.vt (fmaxnum (vec.vt V128:$lhs), (vec.vt V128:$rhs))),
+              (relaxed_max V128:$lhs, V128:$rhs)>;
+    def : Pat<(vec.vt (fmaximumnum (vec.vt V128:$lhs), (vec.vt V128:$rhs))),
+              (relaxed_max V128:$lhs, V128:$rhs)>;
+
+    // Transform pmin/max-supposed patterns to relaxed min max
+    let AddedComplexity = 1 in {
----------------
badumbatish wrote:

the patterns wouldn't take precedence over the following block if not for AddedComplexity

```
// Pseudo-minimum: pmin
def pmin : PatFrags<(ops node:$lhs, node:$rhs), [
                    (vselect (setolt $rhs, $lhs), $rhs, $lhs),
                    (vselect (setole $rhs, $lhs), $rhs, $lhs),
                    (vselect (setogt $lhs, $rhs), $rhs, $lhs),
                    (vselect (setoge $lhs, $rhs), $rhs, $lhs),
                    (vselect (setlt $lhs, $rhs), $lhs, $rhs),
                    (vselect (setle $lhs, $rhs), $lhs, $rhs),
                    (vselect (setgt $lhs, $rhs), $rhs, $lhs),
                    (vselect (setge $lhs, $rhs), $rhs, $lhs)
]>;
defm PMIN : SIMDBinaryFP<pmin, "pmin", 234>;

// Pseudo-maximum: pmax
def pmax : PatFrags<(ops node:$lhs, node:$rhs), [
                    (vselect (setogt $rhs, $lhs), $rhs, $lhs),
                    (vselect (setoge $rhs, $lhs), $rhs, $lhs),
                    (vselect (setolt $lhs, $rhs), $rhs, $lhs),
                    (vselect (setole $lhs, $rhs), $rhs, $lhs),
                    (vselect (setgt $lhs, $rhs), $lhs, $rhs),
                    (vselect (setge $lhs, $rhs), $lhs, $rhs),
                    (vselect (setlt $lhs, $rhs), $rhs, $lhs),
                    (vselect (setle $lhs, $rhs), $rhs, $lhs)
]>;
defm PMAX : SIMDBinaryFP<pmax, "pmax", 235>;
```

https://github.com/llvm/llvm-project/pull/164486