GEP Loop Strength Reduction pass - don't truncate index type

Don't truncate index type when inserting new GEP instructions.

(cherry picked from commit 3afd57f)

Author: pkwasnie-intel

IGC/Compiler/Optimizer/OpenCLPasses/GEPLoopStrengthReduction/GEPLoopStrengthReduction.cpp

@@ -816,6 +816,9 @@ void Analyzer::analyzeGEP(GetElementPtrInst *GEP)
     if (!deconstructSCEV(S, Start, Step))
         return;
 
+    if (S->getType() != Start->getType())
+        Start = SE.getZeroExtendExpr(Start, S->getType());
+
     // Try adding reduction to existing group
     for (auto &c : Candidates)
     {
@@ -908,6 +911,7 @@ bool Analyzer::doInitialValidation(GetElementPtrInst *GEP)
 // parsed and reduced.
 bool Analyzer::deconstructSCEV(const SCEV *S, const SCEV *&Start, int64_t &Step)
 {
+    // Drop ext instructions to analyze nested content.
     S = SCEVHelper::dropExt(S);
 
     // First check if expression can be fully expanded in preheader. If so, no need

IGC/Compiler/tests/GEPLoopStrengthReduction/heuristic_instruction_count.ll

@@ -7,7 +7,7 @@
 ;============================ end_copyright_notice =============================
 
 ; REQUIRES: regkeys
-; RUN: igc_opt --regkey=GEPLSRNewInstructionThreshold=0 -debugify --igc-gep-loop-strength-reduction -check-debugify -S < %s 2>&1 | FileCheck %s --check-prefixes=CHECK,%LLVM_DEPENDENT_CHECK_PREFIX%
+; RUN: igc_opt --regkey=GEPLSRNewInstructionThreshold=0 -debugify --igc-gep-loop-strength-reduction -check-debugify -S < %s 2>&1 | FileCheck %s
 ;
 ; Input:
 ;
@@ -51,7 +51,7 @@ for.cond1.preheader.lr.ph:                        ; preds = %entry
 ; CHECK-LABEL: for.cond1.preheader:
 ; CHECK:              %j.07 = phi i32 [ 0, %for.cond1.preheader.lr.ph ], [ %inc27, %for.inc26 ]
 ; CHECK:              [[MUL:%.*]] = mul i32 %j.07, 10
-; CHECK-LLVM-14-PLUS: [[ZEXT:%.*]] = zext i32 [[MUL]] to i64
+; CHECK:              [[ZEXT:%.*]] = zext i32 [[MUL]] to i64
 ; CHECK:              br i1 true, label %for.body4.lr.ph, label %for.cond7.preheader
 for.cond1.preheader:                              ; preds = %for.cond1.preheader.lr.ph, %for.inc26
   %j.07 = phi i32 [ 0, %for.cond1.preheader.lr.ph ], [ %inc27, %for.inc26 ]
@@ -70,8 +70,7 @@ for.cond7.preheader:                              ; preds = %for.cond1.for.cond7
 ; Loop k2 receives reduction, preheader is modified.
 ;
 ; CHECK-LABEL: for.body11.lr.ph:
-; CHECK-PRE-LLVM-14:  [[GEP1:%.*]] = getelementptr float, float addrspace(1)* %b, i32 [[MUL]]
-; CHECK-LLVM-14-PLUS: [[GEP1:%.*]] = getelementptr float, float addrspace(1)* %b, i64 [[ZEXT]]
+; CHECK:              [[GEP1:%.*]] = getelementptr float, float addrspace(1)* %b, i64 [[ZEXT]]
 ; CHECK:              br label %for.body11
 for.body11.lr.ph:                                 ; preds = %for.cond7.preheader
   %mul13 = mul nsw i32 %j.07, 10

IGC/Compiler/tests/GEPLoopStrengthReduction/one_access_addexpr.ll

@@ -38,7 +38,8 @@ entry:
 ; CHECK:         [[ADD1:%.*]] = add i32 %b, %a
 ; CHECK:         [[MUL:%.*]] = mul i32 %c, [[ADD1]]
 ; CHECK:         [[ADD2:%.*]] = add i32 [[ADD1]], [[MUL]]
-; CHECK:         [[GEP_PHI1:%.*]] = getelementptr i32, i32 addrspace(1)* %p, i32 [[ADD2]]
+; CHECK:         [[ZEXT:%.*]] = zext i32 [[ADD2]] to i64
+; CHECK:         [[GEP_PHI1:%.*]] = getelementptr i32, i32 addrspace(1)* %p, i64 [[ZEXT]]
 ; CHECK:         br label %for.body
 for.body.lr.ph:                                   ; preds = %entry
   br label %for.body

IGC/Compiler/tests/GEPLoopStrengthReduction/three_accesses_addexpr.ll

@@ -45,7 +45,8 @@ entry:
   br i1 %cmp33, label %for.body.lr.ph, label %for.end
 
 ; CHECK-LABEL: for.body.lr.ph:
-; CHECK:         [[GEP_PHI1:%.*]] = getelementptr i32, i32 addrspace(1)* %p, i32 %add4.i.i.i
+; CHECK:         [[ZEXT:%.*]] = zext i32 %add4.i.i.i to i64
+; CHECK:         [[GEP_PHI1:%.*]] = getelementptr i32, i32 addrspace(1)* %p, i64 [[ZEXT]]
 ; CHECK:         br label %for.body
 for.body.lr.ph:                                   ; preds = %entry
   br label %for.body

IGC/Compiler/tests/GEPLoopStrengthReduction/two_accesses_licm.ll

@@ -33,7 +33,8 @@ entry:
 
 ; CHECK-LABEL: for.body.lr.ph:
 ; CHECK:         [[ADD:%.*]] = add i32 %delta, 2
-; CHECK:         [[GEP1:%.*]] = getelementptr i32, i32 addrspace(1)* %p, i32 [[ADD]]
+; CHECK:         [[ZEXT:%.*]] = zext i32 [[ADD]] to i64
+; CHECK:         [[GEP1:%.*]] = getelementptr i32, i32 addrspace(1)* %p, i64 [[ZEXT]]
 ; CHECK:         br label %for.body
 for.body.lr.ph:                                   ; preds = %entry
   br label %for.body