[IR] Split vscale_range interface

Interface is split from:

  std::pair<unsigned, unsigned> getVScaleRangeArgs()

into separate functions for min/max:

  unsigned getVScaleRangeMin();
  Optional<unsigned> getVScaleRangeMax();

Reviewed By: sdesmalen, paulwalker-arm

Differential Revision: https://reviews.llvm.org/D114075

1 files changed, 10 insertions, 8 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 1c41c77..4bec851 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1709,23 +1709,25 @@ static void computeKnownBitsFromOperator(const Operator *I,
             !II->getFunction()->hasFnAttribute(Attribute::VScaleRange))
           break;
 
-        auto VScaleRange = II->getFunction()
-                               ->getFnAttribute(Attribute::VScaleRange)
-                               .getVScaleRangeArgs();
+        auto Attr = II->getFunction()->getFnAttribute(Attribute::VScaleRange);
+        Optional<unsigned> VScaleMax = Attr.getVScaleRangeMax();
 
-        if (VScaleRange.second == 0)
+        if (!VScaleMax)
           break;
 
+        unsigned VScaleMin = Attr.getVScaleRangeMin();
+
         // If vscale min = max then we know the exact value at compile time
         // and hence we know the exact bits.
-        if (VScaleRange.first == VScaleRange.second) {
-          Known.One = VScaleRange.first;
-          Known.Zero = VScaleRange.first;
+        if (VScaleMin == VScaleMax) {
+          Known.One = VScaleMin;
+          Known.Zero = VScaleMin;
           Known.Zero.flipAllBits();
           break;
         }
 
-        unsigned FirstZeroHighBit = 32 - countLeadingZeros(VScaleRange.second);
+        unsigned FirstZeroHighBit =
+            32 - countLeadingZeros(VScaleMax.getValue());
         if (FirstZeroHighBit < BitWidth)
           Known.Zero.setBitsFrom(FirstZeroHighBit);