[APInt] Remove all uses of zextOrSelf, sextOrSelf and truncOrSelf

Most clients only used these methods because they wanted to be able to
extend or truncate to the same bit width (which is a no-op). Now that
the standard zext, sext and trunc allow this, there is no reason to use
the OrSelf versions.

The OrSelf versions additionally have the strange behaviour of allowing
extending to a *smaller* width, or truncating to a *larger* width, which
are also treated as no-ops. A small amount of client code relied on this
(ConstantRange::castOp and MicrosoftCXXNameMangler::mangleNumber) and
needed rewriting.

Differential Revision: https://reviews.llvm.org/D125557

1 files changed, 12 insertions, 4 deletions

diff --git a/llvm/lib/IR/ConstantRange.cpp b/llvm/lib/IR/ConstantRange.cpp
index fb44ca9..c3915ce 100644
--- a/llvm/lib/IR/ConstantRange.cpp
+++ b/llvm/lib/IR/ConstantRange.cpp
@@ -739,15 +739,23 @@ ConstantRange ConstantRange::castOp(Instruction::CastOps CastOp,
   case Instruction::UIToFP: {
     // TODO: use input range if available
     auto BW = getBitWidth();
-    APInt Min = APInt::getMinValue(BW).zextOrSelf(ResultBitWidth);
-    APInt Max = APInt::getMaxValue(BW).zextOrSelf(ResultBitWidth);
+    APInt Min = APInt::getMinValue(BW);
+    APInt Max = APInt::getMaxValue(BW);
+    if (ResultBitWidth > BW) {
+      Min = Min.zext(ResultBitWidth);
+      Max = Max.zext(ResultBitWidth);
+    }
     return ConstantRange(std::move(Min), std::move(Max));
   }
   case Instruction::SIToFP: {
     // TODO: use input range if available
     auto BW = getBitWidth();
-    APInt SMin = APInt::getSignedMinValue(BW).sextOrSelf(ResultBitWidth);
-    APInt SMax = APInt::getSignedMaxValue(BW).sextOrSelf(ResultBitWidth);
+    APInt SMin = APInt::getSignedMinValue(BW);
+    APInt SMax = APInt::getSignedMaxValue(BW);
+    if (ResultBitWidth > BW) {
+      SMin = SMin.sext(ResultBitWidth);
+      SMax = SMax.sext(ResultBitWidth);
+    }
     return ConstantRange(std::move(SMin), std::move(SMax));
   }
   case Instruction::FPTrunc: