[llvm] r247356 - [InstCombineCalls] Use isKnownNonNullAt() to check nullness of passing arguments at callsite

[Chen Li via llvm-commits]

Author: chenli
Date: Thu Sep 10 18:04:49 2015
New Revision: 247356

URL: http://llvm.org/viewvc/llvm-project?rev=247356&view=rev
Log:
[InstCombineCalls] Use isKnownNonNullAt() to check nullness of passing arguments at callsite

Summary: This patch replaces isKnownNonNull() with isKnownNonNullAt() when checking nullness of passing arguments at callsite. In this way it can handle cases where the argument does not have nonnull attribute but has a dominating null check from the CFG.

Reviewers: reames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12779

Added:
    llvm/trunk/test/Transforms/InstCombine/call_nonnull_arg.ll
Modified:
    llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp

Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp?rev=247356&r1=247355&r2=247356&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp (original)
+++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp Thu Sep 10 18:04:49 2015
@@ -1537,7 +1537,7 @@ Instruction *InstCombiner::visitCallSite
   unsigned ArgNo = 0;
   for (Value *V : CS.args()) {
     if (!CS.paramHasAttr(ArgNo+1, Attribute::NonNull) &&
-        isKnownNonNull(V)) {
+        isKnownNonNullAt(V, CS.getInstruction(), DT, TLI)) {
       AttributeSet AS = CS.getAttributes();
       AS = AS.addAttribute(CS.getInstruction()->getContext(), ArgNo+1,
                            Attribute::NonNull);

Added: llvm/trunk/test/Transforms/InstCombine/call_nonnull_arg.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/call_nonnull_arg.ll?rev=247356&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/call_nonnull_arg.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/call_nonnull_arg.ll Thu Sep 10 18:04:49 2015
@@ -0,0 +1,17 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; InstCombine should mark null-checked argument as nonnull at callsite
+declare void @dummy(i32*)
+
+define void @test(i32* %a) {
+; CHECK-LABEL: @test
+; CHECK: call void @dummy(i32* nonnull %a)
+entry:
+  %cond = icmp eq i32* %a, null
+  br i1 %cond, label %is_null, label %not_null
+not_null:
+  call void @dummy(i32* %a)
+  ret void
+is_null:
+  unreachable
+}