[ARM] TypeSize lower bound for ARMCodeGenPrepare

We only try to promote types with are smaller than 16-bits, but we
also need to check that the type is not less than 8-bits.

Differential Revision: https://reviews.llvm.org/D50769

llvm-svn: 339770

llvm/lib/Target/ARM/ARMCodeGenPrepare.cpp

@@ -562,7 +562,7 @@ bool ARMCodeGenPrepare::isLegalToPromote(Value *V) {
 bool ARMCodeGenPrepare::TryToPromote(Value *V) {
   OrigTy = V->getType();
   TypeSize = OrigTy->getPrimitiveSizeInBits();
-  if (TypeSize > 16)
+  if (TypeSize > 16 || TypeSize < 8)
     return false;
 
   if (!isSupportedValue(V) || !shouldPromote(V) || !isLegalToPromote(V))

llvm/test/CodeGen/ARM/arm-cgp-icmps.ll

@@ -256,3 +256,27 @@ define i32 @icmp_not(i16 zeroext %arg0, i16 zeroext %arg1) {
   ret i32 %res
 }
 
+; CHECK-COMMON-LABEL: icmp_i1
+; CHECK-NOT: uxt
+define i32 @icmp_i1(i1* %arg0, i1 zeroext %arg1, i32 %a, i32 %b) {
+entry:
+  %load = load i1, i1* %arg0
+  %not = xor i1 %load, 1
+  %cmp = icmp eq i1 %arg1, %not
+  %res = select i1 %cmp, i32 %a, i32 %b
+  ret i32 %res
+}
+
+; CHECK-COMMON-LABEL: icmp_i7
+; CHECK-COMMON: ldrb
+; CHECK-COMMON: and
+; CHECK-COMMON: cmp
+define i32 @icmp_i7(i7* %arg0, i7 zeroext %arg1, i32 %a, i32 %b) {
+entry:
+  %load = load i7, i7* %arg0
+  %add = add nuw i7 %load, 1
+  %cmp = icmp ult i7 %arg1, %add
+  %res = select i1 %cmp, i32 %a, i32 %b
+  ret i32 %res
+}
+