[PATCH] D90920: [IndVars] IV user should not prevent use widening

[Max Kazantsev via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rGd6dd9385893e: [IndVars] IV user should not prevent use widening (authored by mkazantsev).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D90920/new/

https://reviews.llvm.org/D90920

Files:
  llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
  llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll


Index: llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll
===================================================================
--- llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll
+++ llvm/test/Transforms/IndVarSimplify/widen-loop-comp.ll
@@ -607,13 +607,10 @@
 ; CHECK-NEXT:    [[COND:%.*]] = icmp eq i64 [[INDVARS_IV]], 0
 ; CHECK-NEXT:    br i1 [[COND]], label [[EXIT:%.*]], label [[BACKEDGE]]
 ; CHECK:       backedge:
-; CHECK-NEXT:    [[TMP1:%.*]] = trunc i64 [[INDVARS_IV]] to i32
-; CHECK-NEXT:    [[IV_NEXT:%.*]] = add i32 [[TMP1]], -1
-; CHECK-NEXT:    [[INDEX:%.*]] = zext i32 [[IV_NEXT]] to i64
-; CHECK-NEXT:    [[STORE_ADDR:%.*]] = getelementptr i32, i32* [[P:%.*]], i64 [[INDEX]]
+; CHECK-NEXT:    [[TMP1:%.*]] = add nsw i64 [[INDVARS_IV]], -1
+; CHECK-NEXT:    [[STORE_ADDR:%.*]] = getelementptr i32, i32* [[P:%.*]], i64 [[TMP1]]
 ; CHECK-NEXT:    store i32 1, i32* [[STORE_ADDR]], align 4
-; CHECK-NEXT:    [[LOAD_ADDR:%.*]] = getelementptr i32, i32* [[Q:%.*]], i64 [[INDEX]]
-; CHECK-NEXT:    [[STOP:%.*]] = load i32, i32* [[Q]], align 4
+; CHECK-NEXT:    [[STOP:%.*]] = load i32, i32* [[Q:%.*]], align 4
 ; CHECK-NEXT:    [[LOOP_COND:%.*]] = icmp eq i32 [[STOP]], 0
 ; CHECK-NEXT:    [[INDVARS_IV_NEXT]] = add nsw i64 [[INDVARS_IV]], -1
 ; CHECK-NEXT:    br i1 [[LOOP_COND]], label [[LOOP]], label [[FAILURE:%.*]]
Index: llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -1566,7 +1566,11 @@
   if (!AddRecOp1 || AddRecOp1->getLoop() != L)
     return false;
 
+  // Check that all uses are either s/zext, or narrow def (in case of we are
+  // widening the IV increment).
   for (Use &U : NarrowUse->uses()) {
+    if (U.getUser() == NarrowDef)
+      continue;
     Instruction *User = nullptr;
     if (ExtKind == SignExtended)
       User = dyn_cast<SExtInst>(U.getUser());
@@ -1597,6 +1601,9 @@
   ExtendKindMap[NarrowUse] = ExtKind;
 
   for (Use &U : NarrowUse->uses()) {
+    // Ignore narrow def: it will be removed after the transform.
+    if (U.getUser() == NarrowDef)
+      continue;
     Instruction *User = nullptr;
     if (ExtKind == SignExtended)
       User = cast<SExtInst>(U.getUser());


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