[Attributor] Look through (some) casts in AAValueConstantRangeFloating

Casts can be handled natively by the ConstantRange class. We do limit it
to extends for now as we assume an integer type in different locations.
A TODO and a test case with a FIXME was added to remove that restriction
in the future.

3 files changed, 79 insertions, 7 deletions

diff --git a/llvm/lib/Transforms/IPO/Attributor.cpp b/llvm/lib/Transforms/IPO/Attributor.cpp
index 8b97e3d..f16b9bc 100644
--- a/llvm/lib/Transforms/IPO/Attributor.cpp
+++ b/llvm/lib/Transforms/IPO/Attributor.cpp
@@ -6183,6 +6183,12 @@ struct AAValueConstantRangeFloating : AAValueConstantRangeImpl {
         return;
       }
 
+    // We handle casts in the updateImpl.
+    // TODO: Allow non integers as well.
+    if (CastInst *CI = dyn_cast<CastInst>(&V))
+      if (CI->getOperand(0)->getType()->isIntegerTy())
+        return;
+
     // Otherwise we give up.
     indicatePessimisticFixpoint();
 
@@ -6212,6 +6218,20 @@ struct AAValueConstantRangeFloating : AAValueConstantRangeImpl {
     return T.isValidState();
   }
 
+  bool calculateCastInst(Attributor &A, CastInst *CastI, IntegerRangeState &T,
+                         Instruction *CtxI) {
+    assert(CastI->getNumOperands() == 1 && "Expected cast to be unary!");
+    // TODO: Allow non integers as well.
+    Value &OpV = *CastI->getOperand(0);
+    assert(OpV.getType()->isIntegerTy() && "Expected integer cast");
+
+    auto &OpAA =
+        A.getAAFor<AAValueConstantRange>(*this, IRPosition::value(OpV));
+    T.unionAssumed(
+        OpAA.getAssumed().castOp(CastI->getOpcode(), getState().getBitWidth()));
+    return T.isValidState();
+  }
+
   bool calculateCmpInst(Attributor &A, CmpInst *CmpI, IntegerRangeState &T,
                         Instruction *CtxI) {
     Value *LHS = CmpI->getOperand(0);
@@ -6282,6 +6302,8 @@ struct AAValueConstantRangeFloating : AAValueConstantRangeImpl {
         return calculateBinaryOperator(A, BinOp, T, CtxI);
       else if (auto *CmpI = dyn_cast<CmpInst>(I))
         return calculateCmpInst(A, CmpI, T, CtxI);
+      else if (auto *CastI = dyn_cast<CastInst>(I))
+        return calculateCastInst(A, CastI, T, CtxI);
       else {
         // Give up with other instructions.
         // TODO: Add other instructions
diff --git a/llvm/test/Transforms/Attributor/IPConstantProp/PR16052.ll b/llvm/test/Transforms/Attributor/IPConstantProp/PR16052.ll
index d1fed5a..c3fe2b4 100644
--- a/llvm/test/Transforms/Attributor/IPConstantProp/PR16052.ll
+++ b/llvm/test/Transforms/Attributor/IPConstantProp/PR16052.ll
@@ -4,12 +4,13 @@
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
 
+; FIXME: Use the undef and do not pessimise the result because of it (no !range)
 define i64 @fn2() {
 ; CHECK-LABEL: define {{[^@]+}}@fn2()
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CONV:%.*]] = sext i32 undef to i64
 ; CHECK-NEXT:    [[DIV:%.*]] = sdiv i64 8, [[CONV]]
-; CHECK-NEXT:    [[CALL2:%.*]] = call i64 @fn1(i64 [[DIV]]) #{{[0-9]+}}, !range !0
+; CHECK-NEXT:    [[CALL2:%.*]] = call i64 @fn1(i64 [[DIV]]) #1, !range !0
 ; CHECK-NEXT:    ret i64 [[CALL2]]
 ;
 entry:
@@ -19,6 +20,22 @@ entry:
   ret i64 %call2
 }
 
+define i64 @fn2b(i32 %arg) {
+; CHECK-LABEL: define {{[^@]+}}@fn2b
+; CHECK-SAME: (i32 [[ARG:%.*]])
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    [[CONV:%.*]] = sext i32 [[ARG]] to i64
+; CHECK-NEXT:    [[DIV:%.*]] = sdiv i64 8, [[CONV]]
+; CHECK-NEXT:    [[CALL2:%.*]] = call i64 @fn1(i64 [[DIV]]) #1, !range !0
+; CHECK-NEXT:    ret i64 [[CALL2]]
+;
+entry:
+  %conv = sext i32 %arg to i64
+  %div = sdiv i64 8, %conv
+  %call2 = call i64 @fn1(i64 %div)
+  ret i64 %call2
+}
+
 define internal i64 @fn1(i64 %p1) {
 ; CHECK-LABEL: define {{[^@]+}}@fn1
 ; CHECK-SAME: (i64 returned [[P1:%.*]])
diff --git a/llvm/test/Transforms/Attributor/range.ll b/llvm/test/Transforms/Attributor/range.ll
index 76ae688..0bdf83e 100644
--- a/llvm/test/Transforms/Attributor/range.ll
+++ b/llvm/test/Transforms/Attributor/range.ll
@@ -665,9 +665,38 @@ entry:
   ret i1 %cmp6
 }
 
-; FIXME: We do not look through the zext here.
 define dso_local i32 @select_zext(i32 %a) local_unnamed_addr #0 {
-; CHECK-LABEL: define {{[^@]+}}@select_zext
+; OLD_PM-LABEL: define {{[^@]+}}@select_zext
+; OLD_PM-SAME: (i32 [[A:%.*]]) local_unnamed_addr
+; OLD_PM-NEXT:  entry:
+; OLD_PM-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[A]], 5
+; OLD_PM-NEXT:    [[DOT:%.*]] = select i1 [[CMP]], i32 1, i32 2
+; OLD_PM-NEXT:    [[CMP1:%.*]] = icmp sgt i32 [[A]], 10
+; OLD_PM-NEXT:    [[Y_0_V:%.*]] = select i1 [[CMP1]], i32 1, i32 2
+; OLD_PM-NEXT:    [[Y_0:%.*]] = add nuw nsw i32 [[DOT]], [[Y_0_V]]
+; OLD_PM-NEXT:    [[CMP6:%.*]] = icmp eq i32 [[Y_0]], 5
+; OLD_PM-NEXT:    [[DOT13:%.*]] = zext i1 [[CMP6]] to i32
+; OLD_PM-NEXT:    ret i32 [[DOT13]]
+;
+; NEW_PM-LABEL: define {{[^@]+}}@select_zext
+; NEW_PM-SAME: (i32 [[A:%.*]]) local_unnamed_addr
+; NEW_PM-NEXT:  entry:
+; NEW_PM-NEXT:    ret i32 0
+;
+entry:
+  %cmp = icmp sgt i32 %a, 5
+  %. = select i1 %cmp, i32 1, i32 2
+  %cmp1 = icmp sgt i32 %a, 10
+  %y.0.v = select i1 %cmp1, i32 1, i32 2
+  %y.0 = add nuw nsw i32 %., %y.0.v
+  %cmp6 = icmp eq i32 %y.0, 5
+  %.13 = zext i1 %cmp6 to i32
+  ret i32 %.13
+}
+
+; FIXME: We do not look through the ptr casts here.
+define dso_local i64 @select_int2ptr_bitcast_ptr2int(i32 %a) local_unnamed_addr #0 {
+; CHECK-LABEL: define {{[^@]+}}@select_int2ptr_bitcast_ptr2int
 ; CHECK-SAME: (i32 [[A:%.*]]) local_unnamed_addr
 ; CHECK-NEXT:  entry:
 ; CHECK-NEXT:    [[CMP:%.*]] = icmp sgt i32 [[A]], 5
@@ -676,8 +705,10 @@ define dso_local i32 @select_zext(i32 %a) local_unnamed_addr #0 {
 ; CHECK-NEXT:    [[Y_0_V:%.*]] = select i1 [[CMP1]], i32 1, i32 2
 ; CHECK-NEXT:    [[Y_0:%.*]] = add nuw nsw i32 [[DOT]], [[Y_0_V]]
 ; CHECK-NEXT:    [[CMP6:%.*]] = icmp eq i32 [[Y_0]], 5
-; CHECK-NEXT:    [[DOT13:%.*]] = zext i1 [[CMP6]] to i32
-; CHECK-NEXT:    ret i32 [[DOT13]]
+; CHECK-NEXT:    [[I2P:%.*]] = inttoptr i1 [[CMP6]] to i1*
+; CHECK-NEXT:    [[BC:%.*]] = bitcast i1* [[I2P]] to i32*
+; CHECK-NEXT:    [[P2I:%.*]] = ptrtoint i32* [[BC]] to i64
+; CHECK-NEXT:    ret i64 [[P2I]]
 ;
 entry:
   %cmp = icmp sgt i32 %a, 5
@@ -686,8 +717,10 @@ entry:
   %y.0.v = select i1 %cmp1, i32 1, i32 2
   %y.0 = add nuw nsw i32 %., %y.0.v
   %cmp6 = icmp eq i32 %y.0, 5
-  %.13 = zext i1 %cmp6 to i32
-  ret i32 %.13
+  %i2p = inttoptr i1 %cmp6 to i1*
+  %bc = bitcast i1* %i2p to i32*
+  %p2i = ptrtoint i32* %bc to i64
+  ret i64 %p2i
 }
 
 ; }