[BDCE] Also drop poison-generating metadata

The comment was incorrect: !range also applies to calls, and we
do need to drop it in some cases.

Author: nikic

llvm/lib/Transforms/Scalar/BDCE.cpp

@@ -75,11 +75,10 @@ static void clearAssumptionsOfUsers(Instruction *I, DemandedBits &DB) {
     Instruction *J = WorkList.pop_back_val();
 
     // NSW, NUW, and exact are based on operands that might have changed.
-    J->dropPoisonGeneratingFlags();
+    J->dropPoisonGeneratingFlagsAndMetadata();
 
-    // We do not have to worry about llvm.assume or range metadata:
-    // 1. llvm.assume demands its operand, so trivializing can't change it.
-    // 2. range metadata only applies to memory accesses which demand all bits.
+    // We do not have to worry about llvm.assume, because it demands its
+    // operand, so trivializing can't change it.
 
     // If all bits of a user are demanded, then we know that nothing below
     // that in the def-use chain needs to be changed.

llvm/test/Transforms/BDCE/invalidate-assumptions.ll

@@ -124,7 +124,7 @@ define i32 @disjoint_indirect(i64 %x) {
 define i32 @range(i32 %x) {
 ; CHECK-LABEL: define i32 @range(
 ; CHECK-SAME: i32 [[X:%.*]]) {
-; CHECK-NEXT:    [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[X]], i32 100), !range [[RNG0:![0-9]+]]
+; CHECK-NEXT:    [[UMIN:%.*]] = call i32 @llvm.umin.i32(i32 [[X]], i32 100)
 ; CHECK-NEXT:    [[AND:%.*]] = and i32 [[UMIN]], -2
 ; CHECK-NEXT:    ret i32 [[AND]]
 ;
@@ -133,6 +133,3 @@ define i32 @range(i32 %x) {
   %and = and i32 %umin, -2
   ret i32 %and
 }
-;.
-; CHECK: [[RNG0]] = !{i32 1, i32 101}
-;.