Fix legalizePhiInstruction for vector types

Build extra bitcast before zext instruction for correct vector types
legalization

Author: agrabezh

IGC/Compiler/Legalizer/PeepholeTypeLegalizer.cpp

@@ -192,32 +192,34 @@ void PeepholeTypeLegalizer::legalizePhiInstruction(Instruction &I) {
   if (!I.getType()->isIntOrIntVectorTy() || isLegalInteger(srcWidth) || srcWidth == 1) // nothing to legalize
     return;
 
+  unsigned numElements =
+      I.getType()->isVectorTy() ? (unsigned)cast<IGCLLVM::FixedVectorType>(I.getType())->getNumElements() : 1;
   unsigned quotient = 0, promoteToInt = 0;
-  promoteInt(srcWidth, quotient, promoteToInt, DL->getLargestLegalIntTypeSizeInBits());
+  promoteInt(srcWidth * numElements, quotient, promoteToInt, DL->getLargestLegalIntTypeSizeInBits());
 
   PHINode *oldPhi = cast<PHINode>(&I);
   Value *result = nullptr;
 
   if (quotient > 1) {
-    unsigned numElements =
-        I.getType()->isVectorTy() ? (unsigned)cast<IGCLLVM::FixedVectorType>(I.getType())->getNumElements() : 1;
-    Type *newVecType =
-        IGCLLVM::FixedVectorType::get(Type::getIntNTy(I.getContext(), promoteToInt), quotient * numElements);
+    Type *newVecType = IGCLLVM::FixedVectorType::get(Type::getIntNTy(I.getContext(), promoteToInt), quotient);
     Type *newLargeIntType = Type::getIntNTy(I.getContext(), promoteToInt * quotient);
+    Type *newOrigIntType = Type::getIntNTy(I.getContext(), srcWidth * numElements);
 
     PHINode *newPhi = m_builder->CreatePHI(newVecType, oldPhi->getNumIncomingValues());
     for (unsigned i = 0; i < oldPhi->getNumIncomingValues(); i++) {
       Value *incomingValue = oldPhi->getIncomingValue(i);
 
       m_builder->SetInsertPoint(oldPhi->getIncomingBlock(i)->getTerminator());
-      Value *newLargeIntValue = m_builder->CreateZExt(incomingValue, newLargeIntType);
+      Value *newOrigValue = m_builder->CreateBitCast(incomingValue, newOrigIntType);
+      Value *newLargeIntValue = m_builder->CreateZExt(newOrigValue, newLargeIntType);
       Value *newVecValue = m_builder->CreateBitCast(newLargeIntValue, newVecType);
       newPhi->addIncoming(newVecValue, oldPhi->getIncomingBlock(i));
     }
     // Cast back to original type
     m_builder->SetInsertPoint(newPhi->getParent()->getFirstNonPHI());
     Value *NewLargeIntPhi = m_builder->CreateBitCast(newPhi, newLargeIntType);
-    result = m_builder->CreateTrunc(NewLargeIntPhi, oldPhi->getType());
+    Value *NewOrigIntPhi = m_builder->CreateTrunc(NewLargeIntPhi, newOrigIntType);
+    result = m_builder->CreateBitCast(NewOrigIntPhi, oldPhi->getType());
   } else {
     // quotient == 1 (integer promotion)
     Type *newType = Type::getIntNTy(I.getContext(), promoteToInt);

IGC/Compiler/tests/PeepholeTypeLegalizer/phi_legalize.ll

@@ -0,0 +1,56 @@
+;=========================== begin_copyright_notice ============================
+;
+; Copyright (C) 2025 Intel Corporation
+;
+; SPDX-License-Identifier: MIT
+;
+;============================ end_copyright_notice =============================
+
+; REQUIRES: llvm-14-plus
+; RUN: igc_opt --opaque-pointers -igc-int-type-legalizer -S < %s | FileCheck %s
+
+; Test checks phi types legalization
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v16:16:16-v24:32:32-v32:32:32-v48:64:64-v64:64:64-v96:128:128-v128:128:128-v192:256:256-v256:256:256-v512:512:512-v1024:1024:1024-n8:16:32-p2490368:32:32:32"
+
+define void @test_2xi256(i1 %flag) {
+; CHECK-LABEL: define void @test_2xi256
+; CHECK: = phi <16 x i32> [ zeroinitializer, %bb1 ], [ zeroinitializer, %bb2 ]
+bb:
+  br i1 %flag, label %bb1, label %bb2
+
+bb1:                                              ; preds = %bb
+  br label %bb3
+
+bb2:                                              ; preds = %bb
+  br label %bb3
+
+bb3:                                              ; preds = %bb2, %bb1
+  %tmp = phi <2 x i256> [ zeroinitializer, %bb1 ], [ zeroinitializer, %bb2 ]
+  br label %bb4
+
+bb4:                                              ; preds = %bb3
+  ret void
+}
+
+define void @test_2xi80(i1 %flag) {
+; CHECK-LABEL: define void @test_2xi80
+; CHECK: = phi <5 x i32> [ zeroinitializer, %bb1 ], [ zeroinitializer, %bb2 ]
+bb:
+  br i1 %flag, label %bb1, label %bb2
+
+bb1:                                              ; preds = %bb
+  br label %bb3
+
+bb2:                                              ; preds = %bb
+  br label %bb3
+
+bb3:                                              ; preds = %bb2, %bb1
+  %tmp = phi <2 x i80> [ zeroinitializer, %bb1 ], [ zeroinitializer, %bb2 ]
+  br label %bb4
+
+bb4:                                              ; preds = %bb3
+  ret void
+}
+
+!igc.functions = !{}