[SDAG] Lower range attribute to AssertZext (#95450)

Add support for range attributes on calls, in addition to range metadata.

Author: andjo403

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -4487,6 +4487,17 @@ static const MDNode *getRangeMetadata(const Instruction &I) {
   return I.getMetadata(LLVMContext::MD_range);
 }
 
+static std::optional<ConstantRange> getRange(const Instruction &I) {
+  if (const auto *CB = dyn_cast<CallBase>(&I)) {
+    // see comment in getRangeMetadata about this check
+    if (CB->hasRetAttr(Attribute::NoUndef))
+      return CB->getRange();
+  }
+  if (const MDNode *Range = getRangeMetadata(I))
+    return getConstantRangeFromMetadata(*Range);
+  return std::nullopt;
+}
+
 void SelectionDAGBuilder::visitLoad(const LoadInst &I) {
   if (I.isAtomic())
     return visitAtomicLoad(I);
@@ -10230,19 +10241,16 @@ void SelectionDAGBuilder::visitVACopy(const CallInst &I) {
 SDValue SelectionDAGBuilder::lowerRangeToAssertZExt(SelectionDAG &DAG,
                                                     const Instruction &I,
                                                     SDValue Op) {
-  const MDNode *Range = getRangeMetadata(I);
-  if (!Range)
-    return Op;
+  std::optional<ConstantRange> CR = getRange(I);
 
-  ConstantRange CR = getConstantRangeFromMetadata(*Range);
-  if (CR.isFullSet() || CR.isEmptySet() || CR.isUpperWrapped())
+  if (!CR || CR->isFullSet() || CR->isEmptySet() || CR->isUpperWrapped())
     return Op;
 
-  APInt Lo = CR.getUnsignedMin();
+  APInt Lo = CR->getUnsignedMin();
   if (!Lo.isMinValue())
     return Op;
 
-  APInt Hi = CR.getUnsignedMax();
+  APInt Hi = CR->getUnsignedMax();
   unsigned Bits = std::max(Hi.getActiveBits(),
                            static_cast<unsigned>(IntegerType::MIN_INT_BITS));
 

llvm/test/CodeGen/AArch64/lower-range-metadata-func-call.ll

@@ -34,6 +34,28 @@ entry:
   ret i32 %and
 }
 
+; and can be eliminated
+; CHECK-LABEL: {{^}}test_call_known_max_range_attr:
+; CHECK: bl foo
+; CHECK-NOT: and
+; CHECK: ret
+define i32 @test_call_known_max_range_attr() #0 {
+entry:
+  %id = tail call noundef range(i32 0, 1024) i32 @foo()
+  %and = and i32 %id, 1023
+  ret i32 %and
+}
+
+; CHECK-LABEL: {{^}}test_call_known_max_range_attr_no_noundef:
+; CHECK: bl foo
+; CHECK: and w{{[0-9]+}}, w0, #0x3ff
+; CHECK: ret
+define i32 @test_call_known_max_range_attr_no_noundef() #0 {
+entry:
+  %id = tail call range(i32 0, 1024) i32 @foo()
+  %and = and i32 %id, 1023
+  ret i32 %and
+}
 
 declare i32 @foo()
 

llvm/test/CodeGen/X86/legalize-vec-assertzext.ll

@@ -34,6 +34,24 @@ define i64 @widen_assertzext(ptr %x) nounwind {
   ret i64 %d
 }
 
+define i64 @widen_assertzext_range_attr(ptr %x) nounwind {
+; CHECK-LABEL: widen_assertzext_range_attr:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    pushq %rax
+; CHECK-NEXT:    callq test2@PLT
+; CHECK-NEXT:    movb $127, %al
+; CHECK-NEXT:    kmovw %eax, %k1
+; CHECK-NEXT:    vpexpandq %zmm0, %zmm0 {%k1} {z}
+; CHECK-NEXT:    vextracti32x4 $3, %zmm0, %xmm0
+; CHECK-NEXT:    vmovq %xmm0, %rax
+; CHECK-NEXT:    popq %rcx
+; CHECK-NEXT:    vzeroupper
+; CHECK-NEXT:    retq
+  %e = call noundef range(i64 0, 2) <7 x i64> @test2()
+  %d = extractelement <7 x i64> %e, i32 6
+  ret i64 %d
+}
+
 declare  <16 x i64> @test()
 declare  <7 x i64> @test2()
 !0 = !{ i64 0, i64 2 }