Revert "[clang][CodeGen] Implicit Conversion Sanitizer: handle increment/decrement (PR44054)"

The asssertion that was added does not hold,
breaks on test-suite/MultiSource/Applications/SPASS/analyze.c
Will reduce the testcase and revisit.

This reverts commit 9872ea4ed1de4c49300430e4f1f4dfc110a79ab9, 870f3542d3e0d06d208442bdca6482866b59171b.

1 files changed, 3 insertions, 33 deletions

diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index 953ced9168c..82297664064 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -2419,39 +2419,9 @@ ScalarExprEmitter::EmitScalarPrePostIncDec(const UnaryOperator *E, LValue LV,
 
   // Most common case by far: integer increment.
   } else if (type->isIntegerType()) {
-    assert((!type->isPromotableIntegerType() ||
-            (type->isSignedIntegerOrEnumerationType() ||
-             CGF.getContext()
-                 .getPromotedIntegerType(type)
-                 ->isSignedIntegerOrEnumerationType())) &&
-           "The following check expects that if we do promotion, at least one "
-           "of the types (either base or promoted) will be signed.");
-    if (CGF.SanOpts.hasOneOf(
-            SanitizerKind::ImplicitIntegerArithmeticValueChange) &&
-        type->isPromotableIntegerType()) {
-      // While `x += 1` (for `x` with width less than int) is modeled as
-      // promotion+arithmetics+demotion, and we can catch lossy demotion with
-      // ease; inc/dec with width less than int can't overflow because of
-      // promotion rules, so we omit promotion+demotion, which means that we can
-      // not catch lossy "demotion". Because we still want to catch these cases
-      // when the sanitizer is enabled, we perform the promotion, then perform
-      // the increment/decrement in the wider type, and finally
-      // perform the demotion. This will catch lossy demotions.
-
-      QualType promotedType = CGF.getContext().getPromotedIntegerType(type);
-      assert(promotedType != type && "Shouldn't promote to the same type.");
-      value = EmitScalarConversion(value, type, promotedType, E->getExprLoc());
-      Value *amt = llvm::ConstantInt::get(value->getType(), amount, true);
-      value = Builder.CreateAdd(value, amt, isInc ? "inc" : "dec");
-      // Do pass non-default ScalarConversionOpts so that sanitizer check is
-      // emitted.
-      value = EmitScalarConversion(value, promotedType, type, E->getExprLoc(),
-                                   ScalarConversionOpts(CGF.SanOpts));
-
-      // Note that signed integer inc/dec with width less than int can't
-      // overflow because of promotion rules; we're just eliding a few steps
-      // here.
-    } else if (E->canOverflow() && type->isSignedIntegerOrEnumerationType()) {
+    // Note that signed integer inc/dec with width less than int can't
+    // overflow because of promotion rules; we're just eliding a few steps here.
+    if (E->canOverflow() && type->isSignedIntegerOrEnumerationType()) {
       value = EmitIncDecConsiderOverflowBehavior(E, value, isInc);
     } else if (E->canOverflow() && type->isUnsignedIntegerType() &&
                CGF.SanOpts.has(SanitizerKind::UnsignedIntegerOverflow)) {