[ValueTracking] enhance matching of umin/umax with 'not' operands

The cmyk test is based on the known regression that resulted from:
rGf2fbdf76d8d0

This improves on the equivalent signed min/max change:
rG867f0c3c4d8c

The underlying icmp equivalence is:
  ~X pred ~Y --> Y pred X

For an icmp with constant, canonicalization results in a swapped pred:
  ~X < C -->  X > ~C

1 files changed, 25 insertions, 11 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 01025ab..4fa43a3 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -5157,6 +5157,31 @@ static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
   if (SPR.Flavor != SelectPatternFlavor::SPF_UNKNOWN)
     return SPR;
 
+  // Look through 'not' ops to find disguised min/max.
+  // (X > Y) ? ~X : ~Y ==> (~X < ~Y) ? ~X : ~Y ==> MIN(~X, ~Y)
+  // (X < Y) ? ~X : ~Y ==> (~X > ~Y) ? ~X : ~Y ==> MAX(~X, ~Y)
+  if (CmpLHS == getNotValue(TrueVal) && CmpRHS == getNotValue(FalseVal)) {
+    switch (Pred) {
+    case CmpInst::ICMP_SGT: return {SPF_SMIN, SPNB_NA, false};
+    case CmpInst::ICMP_SLT: return {SPF_SMAX, SPNB_NA, false};
+    case CmpInst::ICMP_UGT: return {SPF_UMIN, SPNB_NA, false};
+    case CmpInst::ICMP_ULT: return {SPF_UMAX, SPNB_NA, false};
+    default: break;
+    }
+  }
+
+  // (X > Y) ? ~Y : ~X ==> (~X < ~Y) ? ~Y : ~X ==> MAX(~Y, ~X)
+  // (X < Y) ? ~Y : ~X ==> (~X > ~Y) ? ~Y : ~X ==> MIN(~Y, ~X)
+  if (CmpLHS == getNotValue(FalseVal) && CmpRHS == getNotValue(TrueVal)) {
+    switch (Pred) {
+    case CmpInst::ICMP_SGT: return {SPF_SMAX, SPNB_NA, false};
+    case CmpInst::ICMP_SLT: return {SPF_SMIN, SPNB_NA, false};
+    case CmpInst::ICMP_UGT: return {SPF_UMAX, SPNB_NA, false};
+    case CmpInst::ICMP_ULT: return {SPF_UMIN, SPNB_NA, false};
+    default: break;
+    }
+  }
+
   if (Pred != CmpInst::ICMP_SGT && Pred != CmpInst::ICMP_SLT)
     return {SPF_UNKNOWN, SPNB_NA, false};
 
@@ -5174,17 +5199,6 @@ static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
       match(TrueVal, m_NSWSub(m_Specific(CmpLHS), m_Specific(CmpRHS))))
     return {Pred == CmpInst::ICMP_SGT ? SPF_SMAX : SPF_SMIN, SPNB_NA, false};
 
-  // Look through 'not' ops to find disguised signed min/max.
-  // (X >s Y) ? ~X : ~Y ==> (~X <s ~Y) ? ~X : ~Y ==> SMIN(~X, ~Y)
-  // (X <s Y) ? ~X : ~Y ==> (~X >s ~Y) ? ~X : ~Y ==> SMAX(~X, ~Y)
-  if (CmpLHS == getNotValue(TrueVal) && CmpRHS == getNotValue(FalseVal))
-    return {Pred == CmpInst::ICMP_SGT ? SPF_SMIN : SPF_SMAX, SPNB_NA, false};
-
-  // (X >s Y) ? ~Y : ~X ==> (~X <s ~Y) ? ~Y : ~X ==> SMAX(~Y, ~X)
-  // (X <s Y) ? ~Y : ~X ==> (~X >s ~Y) ? ~Y : ~X ==> SMIN(~Y, ~X)
-  if (CmpLHS == getNotValue(FalseVal) && CmpRHS == getNotValue(TrueVal))
-    return {Pred == CmpInst::ICMP_SGT ? SPF_SMAX : SPF_SMIN, SPNB_NA, false};
-
   const APInt *C1;
   if (!match(CmpRHS, m_APInt(C1)))
     return {SPF_UNKNOWN, SPNB_NA, false};