[llvm] [Matrix] Propagate shape information through (f)abs insts (PR #141704)

[Florian Hahn via llvm-commits]

================
@@ -2198,6 +2210,49 @@ class LowerMatrixIntrinsics {
     return true;
   }
 
+  /// Lower uniform shape intrinsics, if shape information is available.
+  bool VisitUniformIntrinsic(IntrinsicInst *Inst) {
+    auto I = ShapeMap.find(Inst);
+    if (I == ShapeMap.end())
+      return false;
+
+    IRBuilder<> Builder(Inst);
+    ShapeInfo &Shape = I->second;
+
+    MatrixTy Result;
+
+    switch (Inst->getIntrinsicID()) {
+    case Intrinsic::abs:
+    case Intrinsic::fabs: {
+      Value *Op = Inst->getOperand(0);
+
+      MatrixTy M = getMatrix(Op, Shape, Builder);
+
+      Builder.setFastMathFlags(getFastMathFlags(Inst));
+
+      for (unsigned I = 0; I < Shape.getNumVectors(); ++I)
----------------
fhahn wrote:

Does using `vectors()` work here?

```suggestion
      for (auto &Vector : M.vectors()) {
```

https://github.com/llvm/llvm-project/pull/141704