[llvm] 6a19cb8 - [ConstantFold] Support pointers in reinterpret load folding

[Nikita Popov via llvm-commits]

Author: Nikita Popov
Date: 2022-01-21T09:13:37+01:00
New Revision: 6a19cb837c9b2ca14642bb0a8f1234903e4430d0

URL: https://github.com/llvm/llvm-project/commit/6a19cb837c9b2ca14642bb0a8f1234903e4430d0
DIFF: https://github.com/llvm/llvm-project/commit/6a19cb837c9b2ca14642bb0a8f1234903e4430d0.diff

LOG: [ConstantFold] Support pointers in reinterpret load folding

Peculiarly, the necessary code to handle pointers (including the
check for non-integral address spaces) is already in place,
because we were already allowing vectors of pointers here, just
not plain pointers.

Added: 
    

Modified: 
    llvm/lib/Analysis/ConstantFolding.cpp
    llvm/test/Transforms/InstSimplify/ConstProp/loads.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index d42086a10ee14..c834ecf107915 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -558,7 +558,7 @@ Constant *FoldReinterpretLoadFromConst(Constant *C, Type *LoadTy,
     // that address spaces don't matter here since we're not going to result in
     // an actual new load.
     if (!LoadTy->isHalfTy() && !LoadTy->isFloatTy() && !LoadTy->isDoubleTy() &&
-        !LoadTy->isVectorTy())
+        !LoadTy->isPointerTy() && !LoadTy->isVectorTy())
       return nullptr;
 
     Type *MapTy = Type::getIntNTy(

diff  --git a/llvm/test/Transforms/InstSimplify/ConstProp/loads.ll b/llvm/test/Transforms/InstSimplify/ConstProp/loads.ll
index 65daa324f7468..990063be0468e 100644
--- a/llvm/test/Transforms/InstSimplify/ConstProp/loads.ll
+++ b/llvm/test/Transforms/InstSimplify/ConstProp/loads.ll
@@ -340,9 +340,11 @@ define i32 @load_all_undef() {
 @g_i8_data = constant [16 x i8] c"\01\00\00\00\00\00\00\00\00\00\00\00\00\00\00\00"
 
 define i64* @load_ptr_from_i8_data() {
-; CHECK-LABEL: @load_ptr_from_i8_data(
-; CHECK-NEXT:    [[V:%.*]] = load i64*, i64** bitcast ([16 x i8]* @g_i8_data to i64**), align 8
-; CHECK-NEXT:    ret i64* [[V]]
+; LE-LABEL: @load_ptr_from_i8_data(
+; LE-NEXT:    ret i64* inttoptr (i64 1 to i64*)
+;
+; BE-LABEL: @load_ptr_from_i8_data(
+; BE-NEXT:    ret i64* inttoptr (i64 72057594037927936 to i64*)
 ;
   %v = load i64*, i64** bitcast ([16 x i8]* @g_i8_data to i64**)
   ret i64* %v