[llvm] [IR] Reject unhandled assume bundles and seperate them from normal attributes (PR #197007)

[Nikolas Klauser via llvm-commits]

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@@ -1088,13 +1087,15 @@ void llvm::computeKnownBitsFromContext(const Value *V, KnownBits &Known,
            "Got assumption for the wrong function!");
 
     if (Elem.Index != AssumptionCache::ExprResultIdx) {
-      if (!V->getType()->isPointerTy())
-        continue;
-      if (RetainedKnowledge RK = getKnowledgeFromBundle(
-              *I, I->bundle_op_info_begin()[Elem.Index])) {
-        if (RK.WasOn == V && RK.AttrKind == Attribute::Alignment &&
-            isPowerOf2_64(RK.ArgValue) && isValidAssumeForContext(I, Q))
-          Known.Zero.setLowBits(Log2_64(RK.ArgValue));
+      if (auto OBU = I->getOperandBundleAt(Elem.Index);
+          getBundleAttrFromOBU(OBU) == BundleAttr::Align) {
+        auto [Ptr, _, Alignment, Offset] = getAssumeAlignInfo(OBU);
+        assert(Ptr == V);
+        if (!Alignment || !isPowerOf2_64(*Alignment))
+          continue;
+        auto AlignVal = MinAlign(Offset.value_or(0), *Alignment);
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philnik777 wrote:

Indeed. Added regression tests to `ValueTracking/assume.ll` (I think this should be the right place?). Fixed by setting `Offset` to zero if it doesn't exist inside `getAssumeAlignInfo` and bailing in the `nullopt` case.

https://github.com/llvm/llvm-project/pull/197007