[llvm] d06d43a - [VPlan] Add printPhiOperands to VPPhiAccessors, use for wide phis.

[Florian Hahn via llvm-commits]

Author: Florian Hahn
Date: 2025-05-08T20:56:48+01:00
New Revision: d06d43a9e8cb5db84e6ee3557b6244e14a291def

URL: https://github.com/llvm/llvm-project/commit/d06d43a9e8cb5db84e6ee3557b6244e14a291def
DIFF: https://github.com/llvm/llvm-project/commit/d06d43a9e8cb5db84e6ee3557b6244e14a291def.diff

LOG: [VPlan] Add printPhiOperands to VPPhiAccessors, use for wide phis.

(NFC modulo debug output changes)

Add generic helper to print phi operands (incoming values) together with
their incoming blocks.

As more and more transforms are added, keeping the incoming blocks of
phis becomes more important. Print incoming blocks via VPPhiAcessors, to
make debugging easier.

Added: 
    

Modified: 
    llvm/lib/Transforms/Vectorize/VPlan.h
    llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
    llvm/test/Transforms/LoopVectorize/vplan-printing-outer-loop.ll
    llvm/unittests/Transforms/Vectorize/VPlanHCFGTest.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Transforms/Vectorize/VPlan.h b/llvm/lib/Transforms/Vectorize/VPlan.h
index cb35557064d7e..4068b02a97acc 100644
--- a/llvm/lib/Transforms/Vectorize/VPlan.h
+++ b/llvm/lib/Transforms/Vectorize/VPlan.h
@@ -1201,6 +1201,11 @@ class VPPhiAccessors {
 
   /// Returns the number of incoming values, also number of incoming blocks.
   unsigned getNumIncoming() const { return getAsRecipe()->getNumOperands(); }
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+  /// Print the recipe.
+  void printPhiOperands(raw_ostream &O, VPSlotTracker &SlotTracker) const;
+#endif
 };
 
 /// An overlay for VPIRInstructions wrapping PHI nodes enabling convenient use

diff  --git a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
index e164f36adb98c..7239503470720 100644
--- a/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
+++ b/llvm/lib/Transforms/Vectorize/VPlanRecipes.cpp
@@ -1197,6 +1197,20 @@ void VPIRPhi::execute(VPTransformState &State) {
   State.Builder.SetInsertPoint(Phi->getParent(), std::next(Phi->getIterator()));
 }
 
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+void VPPhiAccessors::printPhiOperands(raw_ostream &O,
+                                      VPSlotTracker &SlotTracker) const {
+  interleaveComma(enumerate(getAsRecipe()->operands()), O,
+                  [this, &O, &SlotTracker](auto Op) {
+                    O << "[ ";
+                    Op.value()->printAsOperand(O, SlotTracker);
+                    O << ", ";
+                    getIncomingBlock(Op.index())->printAsOperand(O);
+                    O << " ]";
+                  });
+}
+#endif
+
 #if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
 void VPIRPhi::print(raw_ostream &O, const Twine &Indent,
                     VPSlotTracker &SlotTracker) const {
@@ -3809,7 +3823,7 @@ void VPWidenPHIRecipe::print(raw_ostream &O, const Twine &Indent,
 
   printAsOperand(O, SlotTracker);
   O << " = phi ";
-  printOperands(O, SlotTracker);
+  printPhiOperands(O, SlotTracker);
 }
 #endif
 

diff  --git a/llvm/test/Transforms/LoopVectorize/vplan-printing-outer-loop.ll b/llvm/test/Transforms/LoopVectorize/vplan-printing-outer-loop.ll
index fe845ae74cbee..6804817c402bd 100644
--- a/llvm/test/Transforms/LoopVectorize/vplan-printing-outer-loop.ll
+++ b/llvm/test/Transforms/LoopVectorize/vplan-printing-outer-loop.ll
@@ -13,14 +13,14 @@ define void @foo(i64 %n) {
 ; CHECK-NEXT: Successor(s): outer.header
 ; CHECK-EMPTY:
 ; CHECK-NEXT: outer.header:
-; CHECK-NEXT:   WIDEN-PHI ir<%outer.iv> = phi ir<%outer.iv.next>, ir<0>
+; CHECK-NEXT:   WIDEN-PHI ir<%outer.iv> = phi [ ir<%outer.iv.next>, outer.latch ], [ ir<0>, ir-bb<entry> ]
 ; CHECK-NEXT:   EMIT ir<%gep.1> = getelementptr ir<@arr2>, ir<0>, ir<%outer.iv>
 ; CHECK-NEXT:   EMIT store ir<%outer.iv>, ir<%gep.1>
 ; CHECK-NEXT:   EMIT ir<%add> = add ir<%outer.iv>, ir<%n>
 ; CHECK-NEXT: Successor(s): inner
 ; CHECK-EMPTY:
 ; CHECK-NEXT: inner:
-; CHECK-NEXT:   WIDEN-PHI ir<%inner.iv> = phi ir<%inner.iv.next>, ir<0>
+; CHECK-NEXT:   WIDEN-PHI ir<%inner.iv> = phi [ ir<%inner.iv.next>, inner ], [ ir<0>, outer.header ]
 ; CHECK-NEXT:   EMIT ir<%gep.2> = getelementptr ir<@arr>, ir<0>, ir<%inner.iv>, ir<%outer.iv>
 ; CHECK-NEXT:   EMIT store ir<%add>, ir<%gep.2>
 ; CHECK-NEXT:   EMIT ir<%inner.iv.next> = add ir<%inner.iv>, ir<1>

diff  --git a/llvm/unittests/Transforms/Vectorize/VPlanHCFGTest.cpp b/llvm/unittests/Transforms/Vectorize/VPlanHCFGTest.cpp
index f33e9615d4176..434a8656afba2 100644
--- a/llvm/unittests/Transforms/Vectorize/VPlanHCFGTest.cpp
+++ b/llvm/unittests/Transforms/Vectorize/VPlanHCFGTest.cpp
@@ -122,7 +122,7 @@ compound=true
     N2 [label =
       "vector.body:\l" +
       "  EMIT vp\<%2\> = CANONICAL-INDUCTION ir\<0\>, vp\<%index.next\>\l" +
-      "  WIDEN-PHI ir\<%indvars.iv\> = phi ir\<0\>, ir\<%indvars.iv.next\>\l" +
+      "  WIDEN-PHI ir\<%indvars.iv\> = phi [ ir\<0\>, vector.ph ], [ ir\<%indvars.iv.next\>, vector.body ]\l" +
       "  EMIT ir\<%arr.idx\> = getelementptr ir\<%A\>, ir\<%indvars.iv\>\l" +
       "  EMIT ir\<%l1\> = load ir\<%arr.idx\>\l" +
       "  EMIT ir\<%res\> = add ir\<%l1\>, ir\<10\>\l" +
@@ -291,7 +291,7 @@ compound=true
     N2 [label =
       "vector.body:\l" +
       "  EMIT vp\<%2\> = CANONICAL-INDUCTION ir\<0\>, vp\<%index.next\>\l" +
-      "  WIDEN-PHI ir\<%iv\> = phi ir\<0\>, ir\<%iv.next\>\l" +
+      "  WIDEN-PHI ir\<%iv\> = phi [ ir\<0\>, vector.ph ], [ ir\<%iv.next\>, loop.latch ]\l" +
       "  EMIT ir\<%arr.idx\> = getelementptr ir\<%A\>, ir\<%iv\>\l" +
       "  EMIT ir\<%l1\> = load ir\<%arr.idx\>\l" +
       "  EMIT ir\<%c\> = icmp ir\<%l1\>, ir\<0\>\l" +