[PATCH] D41072: [InstCombine] Fix PR35618: Instcombine hangs on single minmax load bitcast.

[Alexey Bataev via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL320407: [InstCombine] Fix PR35618: Instcombine hangs on single minmax load bitcast. (authored by ABataev).

Repository:
  rL LLVM

https://reviews.llvm.org/D41072

Files:
  llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
  llvm/trunk/test/Transforms/InstCombine/multiple-uses-load-bitcast-select.ll


Index: llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
===================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -1344,9 +1344,24 @@
   if (!isMinMaxWithLoads(LoadAddr))
     return false;
 
+  if (!all_of(LI->users(), [LI](User *U) {
+        auto *SI = dyn_cast<StoreInst>(U);
+        return SI && SI->getPointerOperand() != LI &&
+               !SI->getPointerOperand()->isSwiftError();
+      }))
+    return false;
+
+  IC.Builder.SetInsertPoint(LI);
   LoadInst *NewLI = combineLoadToNewType(
       IC, *LI, LoadAddr->getType()->getPointerElementType());
-  combineStoreToNewValue(IC, SI, NewLI);
+  // Replace all the stores with stores of the newly loaded value.
+  for (auto *UI : LI->users()) {
+    auto *SI = cast<StoreInst>(UI);
+    IC.Builder.SetInsertPoint(SI);
+    combineStoreToNewValue(IC, *SI, NewLI);
+    IC.eraseInstFromFunction(*SI);
+  }
+  IC.eraseInstFromFunction(*LI);
   return true;
 }
 
@@ -1375,7 +1390,7 @@
     return eraseInstFromFunction(SI);
 
   if (removeBitcastsFromLoadStoreOnMinMax(*this, SI))
-    return eraseInstFromFunction(SI);
+    return nullptr;
 
   // Replace GEP indices if possible.
   if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Ptr, SI)) {
Index: llvm/trunk/test/Transforms/InstCombine/multiple-uses-load-bitcast-select.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/multiple-uses-load-bitcast-select.ll
+++ llvm/trunk/test/Transforms/InstCombine/multiple-uses-load-bitcast-select.ll
@@ -0,0 +1,30 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S -data-layout="E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-v128:64-a:8:16-n32:64" | FileCheck %s
+
+define void @PR35618(i64* %st1, double* %st2) {
+; CHECK-LABEL: @PR35618(
+; CHECK-NEXT:    [[Y1:%.*]] = alloca double, align 8
+; CHECK-NEXT:    [[Z1:%.*]] = alloca double, align 8
+; CHECK-NEXT:    [[LD1:%.*]] = load double, double* [[Y1]], align 8
+; CHECK-NEXT:    [[LD2:%.*]] = load double, double* [[Z1]], align 8
+; CHECK-NEXT:    [[TMP10:%.*]] = fcmp olt double [[LD1]], [[LD2]]
+; CHECK-NEXT:    [[TMP121:%.*]] = select i1 [[TMP10]], double [[LD1]], double [[LD2]]
+; CHECK-NEXT:    [[TMP1:%.*]] = bitcast i64* [[ST1:%.*]] to double*
+; CHECK-NEXT:    store double [[TMP121]], double* [[TMP1]], align 8
+; CHECK-NEXT:    store double [[TMP121]], double* [[ST2:%.*]], align 8
+; CHECK-NEXT:    ret void
+;
+  %y1 = alloca double
+  %z1 = alloca double
+  %ld1 = load double, double* %y1
+  %ld2 = load double, double* %z1
+  %tmp10 = fcmp olt double %ld1, %ld2
+  %sel = select i1 %tmp10, double* %y1, double* %z1
+  %tmp11 = bitcast double* %sel to i64*
+  %tmp12 = load i64, i64* %tmp11
+  store i64 %tmp12, i64* %st1
+  %bc = bitcast double* %st2 to i64*
+  store i64 %tmp12, i64* %bc
+  ret void
+}
+


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