[PATCH] D64708: [ValueTracking] Look through constant Int2Ptr/Ptr2Int expressions
Johannes Doerfert via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Sun Jul 14 10:54:21 PDT 2019
jdoerfert created this revision.
jdoerfert added reviewers: fhahn, efriedma, spatel, nlopes, sanjoy, lebedev.ri.
Herald added subscribers: bollu, hiraditya.
Herald added a project: LLVM.
This is analogous to the int2ptr/ptr2int instruction handling introduced
in D54956 <https://reviews.llvm.org/D54956>.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D64708
Files:
llvm/lib/Analysis/ValueTracking.cpp
llvm/test/Transforms/FunctionAttrs/nonnull.ll
Index: llvm/test/Transforms/FunctionAttrs/nonnull.ll
===================================================================
--- llvm/test/Transforms/FunctionAttrs/nonnull.ll
+++ llvm/test/Transforms/FunctionAttrs/nonnull.ll
@@ -237,4 +237,14 @@
ret i32 addrspace(3)* %q
}
+; CHECK: define internal nonnull i32* @f2()
+define internal i32* @f2() {
+ ret i32* inttoptr (i64 4 to i32*)
+}
+
+define i32* @f1() {
+ %c = call i32* @f2()
+ ret i32* %c
+}
+
attributes #0 = { "null-pointer-is-valid"="true" }
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -1998,6 +1998,15 @@
// Must be non-zero due to null test above.
return true;
+ if (auto *CE = dyn_cast<ConstantExpr>(C)) {
+ // See the comment for IntToPtr/PtrToInt instructions below.
+ if (CE->getOpcode() == Instruction::IntToPtr ||
+ CE->getOpcode() == Instruction::PtrToInt)
+ if (Q.DL.getTypeSizeInBits(CE->getOperand(0)->getType()) <=
+ Q.DL.getTypeSizeInBits(CE->getType()))
+ return isKnownNonZero(CE->getOperand(0), Depth, Q);
+ }
+
// For constant vectors, check that all elements are undefined or known
// non-zero to determine that the whole vector is known non-zero.
if (auto *VecTy = dyn_cast<VectorType>(C->getType())) {
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