ConstantFolding: Avoid a crash.

[manojgupta]

Summary

Check if the parent basic block and caller exists
before calling CS.getCaller when constant folding
strip.invariant.group instrinsic.

This avoids a crash when the function containing the intrinsic
is being inlined. The instruction is checked for any simplifiction
but has not yet been added to a basic block.

[manojgupta]

Thanks Piotr for the testcase.

[efriedma]

LGTM

[manojgupta]

Thanks for the quick review!

llvm/trunk/lib/Analysis/ConstantFolding.cpp

if (isa<UndefValue>(Operands[0])) {
         return Constant::getNullValue(Ty);
       if (IntrinsicID == Intrinsic::bswap ||
           IntrinsicID == Intrinsic::bitreverse ||
           IntrinsicID == Intrinsic::launder_invariant_group ||
           IntrinsicID == Intrinsic::strip_invariant_group)
         return Operands[0];
     }
 
-    if (isa<ConstantPointerNull>(Operands[0]) &&
-        !NullPointerIsDefined(
-            CS.getCaller(), Operands[0]->getType()->getPointerAddressSpace())) {
+    if (isa<ConstantPointerNull>(Operands[0])) {
       // launder(null) == null == strip(null) iff in addrspace 0
       if (IntrinsicID == Intrinsic::launder_invariant_group ||
-          IntrinsicID == Intrinsic::strip_invariant_group)
+          IntrinsicID == Intrinsic::strip_invariant_group) {
+        // If instruction is not yet put in a basic block (e.g. when cloning
+        // a function during inlining), CS caller may not be available.
+        // So check CS's BB first before querying CS.getCaller.
+        const Function *Caller = CS.getParent() ? CS.getCaller() : nullptr;
+        if (Caller &&
+            !NullPointerIsDefined(
+                Caller, Operands[0]->getType()->getPointerAddressSpace())) {
           return Operands[0];
+        }
         return nullptr;
       }
+    }
 
     if (auto *Op = dyn_cast<ConstantFP>(Operands[0])) {
       if (IntrinsicID == Intrinsic::convert_to_fp16) {
         APFloat Val(Op->getValueAPF());
 
         bool lost = false;
         Val.convert(APFloat::IEEEhalf(), APFloat::rmNearestTiesToEven, &lost);
 

llvm/trunk/test/Transforms/Inline/inline_inv_group.ll

+; RUN: opt < %s -inline -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i8* @callee() alwaysinline {
+; CHECK-LABEL: define i8* @callee()
+    %1 = call i8* @llvm.strip.invariant.group.p0i8(i8* null)
+    ret i8* %1
+}
+
+define i8* @caller() {
+; CHECK-LABEL: define i8* @caller()
+; CHECK-NEXT: call i8* @llvm.strip.invariant.group.p0i8(i8* null)
+    %1 = call i8* @callee()
+    ret i8* %1
+}
+
+declare i8* @llvm.strip.invariant.group.p0i8(i8*)