[PATCH] D9397: llvm.noalias - computeKnownBits should look through them

[Hal Finkel via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rL275036: Teach computeKnownBits to look through returned-argument functions (authored by hfinkel).

Changed prior to commit:
  http://reviews.llvm.org/D9397?vs=63344&id=63450#toc

Repository:
  rL LLVM

http://reviews.llvm.org/D9397

Files:
  llvm/trunk/lib/Analysis/ValueTracking.cpp
  llvm/trunk/test/Transforms/InstCombine/align-attr.ll

Index: llvm/trunk/test/Transforms/InstCombine/align-attr.ll
===================================================================
--- llvm/trunk/test/Transforms/InstCombine/align-attr.ll
+++ llvm/trunk/test/Transforms/InstCombine/align-attr.ll
@@ -13,3 +13,16 @@
 ; CHECK: ret i32
 }
 
+define i32 @foo2(i32* align 32 %a) #0 {
+entry:
+  %v = call i32* @func1(i32* %a)
+  %0 = load i32, i32* %v, align 4
+  ret i32 %0
+
+; CHECK-LABEL: @foo2
+; CHECK-DAG: load i32, i32* %v, align 32
+; CHECK: ret i32
+}
+
+declare i32* @func1(i32* returned) nounwind
+
Index: llvm/trunk/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/trunk/lib/Analysis/ValueTracking.cpp
+++ llvm/trunk/lib/Analysis/ValueTracking.cpp
@@ -1279,11 +1279,16 @@
   }
   case Instruction::Call:
   case Instruction::Invoke:
+    // If range metadata is attached to this call, set known bits from that,
+    // and then intersect with known bits based on other properties of the
+    // function.
     if (MDNode *MD = cast<Instruction>(I)->getMetadata(LLVMContext::MD_range))
       computeKnownBitsFromRangeMetadata(*MD, KnownZero, KnownOne);
-    // If a range metadata is attached to this IntrinsicInst, intersect the
-    // explicit range specified by the metadata and the implicit range of
-    // the intrinsic.
+    if (Value *RV = CallSite(I).getReturnedArgOperand()) {
+      computeKnownBits(RV, KnownZero2, KnownOne2, Depth + 1, Q);
+      KnownZero |= KnownZero2;
+      KnownOne |= KnownOne2;
+    }
     if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
       switch (II->getIntrinsicID()) {
       default: break;


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