[llvm] [GIsel] import min/max rewrites (PR #188267)

[David Green via llvm-commits]

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@@ -2152,6 +2152,28 @@ def AMinusC1PlusC2: GICombineRule<
    [{ return Helper.matchFoldAMinusC1PlusC2(*${root}, ${matchinfo}); }]),
    (apply [{ Helper.applyBuildFn(*${root}, ${matchinfo}); }])>;
 
+// (sub 0, (max X, (sub 0, X))) --> (min X, (sub 0, X))
+def SubSmaxSub: GICombineRule<
+   (defs root:$root),
+   (match (G_SUB $sub, 0, $A),
+          (G_SMAX $max, $A, $sub),
+          (G_SUB $root, 0, $max),
+          [{ return MRI.hasOneNonDBGUse(${sub}.getReg()) &&
+                    MRI.hasOneNonDBGUse(${max}.getReg()); }]),
+   (apply (G_SUB $sub1, 0, $A), 
+          (G_SMIN $root, $A, $sub1))>;
+              
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davemgreen wrote:

Can you remove the whitespace?

https://github.com/llvm/llvm-project/pull/188267