Index: llvm/trunk/lib/Target/ARM/ARMCodeGenPrepare.cpp
===================================================================
--- llvm/trunk/lib/Target/ARM/ARMCodeGenPrepare.cpp
+++ llvm/trunk/lib/Target/ARM/ARMCodeGenPrepare.cpp
@@ -179,9 +179,6 @@
 }
 
 static bool GenerateSignBits(Value *V) {
-  if (auto *Arg = dyn_cast<Argument>(V))
-    return Arg->hasSExtAttr();
-
   if (!isa<Instruction>(V))
     return false;
 
@@ -843,8 +840,8 @@
     }
   } else if (isa<Constant>(V) && !isa<ConstantExpr>(V)) {
     return isSupportedType(V);
-  } else if (auto *Arg = dyn_cast<Argument>(V))
-    return isSupportedType(V) && !Arg->hasSExtAttr();
+  } else if (isa<Argument>(V))
+    return isSupportedType(V);
 
   return isa<BasicBlock>(V);
 }
Index: llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-overflow.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-overflow.ll
+++ llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-overflow.ll
@@ -264,10 +264,9 @@
 }
 
 ; CHECK-LABEL: underflow_if_sub_signext
-; CHECK: uxtb [[UXT1:r[0-9]+]], r1
-; CHECK: sub{{.*}} [[SUB:r[0-9]+]], #11
-; CHECK: uxtb [[UXT_SUB:r[0-9]+]], [[SUB]]
-; CHECK: cmp{{.*}}[[UXT_SUB]]
+; CHECK:      cmp r0, #0
+; CHECK-NEXT: uxtb  r1, r1
+; CHECK-NOT:  xtb
 define i8 @underflow_if_sub_signext(i32 %arg, i8 signext %arg1) {
   %cmp = icmp sgt i32 %arg, 0
   %conv = zext i1 %cmp to i32
Index: llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-phis-ret.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-phis-ret.ll
+++ llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-phis-ret.ll
@@ -184,3 +184,35 @@
   store i8 %conv, i8* %res
   ret i16 %arg1
 }
+
+; CHECK-COMMON-LABEL: signext_bitcast_phi_select
+; CHECK: uxth [[UXT:r[0-9]+]], r0
+; CHECK: sxth [[SXT:r[0-9]+]], [[UXT]]
+; CHECK: cmp [[SXT]],
+; CHECK-NOT: xth
+define i16 @signext_bitcast_phi_select(i16 signext %start, i16* %in) {
+entry:
+  %const = bitcast i16 -1 to i16
+  br label %for.body
+
+for.body:
+  %idx = phi i16 [ %select, %if.else ], [ %start, %entry ]
+  %cmp.i = icmp sgt i16 %idx, %const
+  br i1 %cmp.i, label %exit, label %if.then
+
+if.then:
+  %idx.next = getelementptr i16, i16* %in, i16 %idx
+  %ld = load i16, i16* %idx.next, align 2
+  %cmp1.i = icmp eq i16 %ld, %idx
+  br i1 %cmp1.i, label %exit, label %if.else
+
+if.else:
+  %lobit = lshr i16 %idx, 15
+  %lobit.not = xor i16 %lobit, 1
+  %select = add nuw i16 %lobit.not, %idx
+  br label %for.body
+
+exit:
+  %res = phi i16 [ %ld, %if.then ], [ 0, %for.body ]
+  ret i16 %res
+}
Index: llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-signed.ll
===================================================================
--- llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-signed.ll
+++ llvm/trunk/test/CodeGen/ARM/CGP/arm-cgp-signed.ll
@@ -1,5 +1,5 @@
-; RUN: llc -mtriple=thumbv7m -arm-disable-cgp=false %s -o - | FileCheck %s
-; RUN: llc -mtriple=thumbv8m.main -arm-disable-cgp=false %s -o - | FileCheck %s
+; RUN: llc -mtriple=thumbv7em -arm-disable-cgp=false %s -o - | FileCheck %s
+; RUN: llc -mtriple=thumbv8m.main -mattr=+dsp -arm-disable-cgp=false %s -o - | FileCheck %s
 ; RUN: llc -mtriple=thumbv7 %s -arm-disable-cgp=false -o - | FileCheck %s
 ; RUN: llc -mtriple=armv8 %s -arm-disable-cgp=false -o - | FileCheck %s
 
@@ -45,8 +45,8 @@
 
 ; CHECK-LABEL: test_signext_b
 ; CHECK: ldrb [[LDR:r[0-9]+]], [r0]
-; CHECK: sxtb [[SXT:r[0-9]+]], [[LDR]]
-; CHECK: cm{{.*}} [[SXT]]
+; CHECK: uxtab [[UXT:r[0-9]+]], [[LDR]], r1
+; CHECK: cm{{.*}} [[UXT]], #128
 define i32 @test_signext_b(i8* %ptr, i8 signext %arg) {
 entry:
   %0 = load i8, i8* %ptr, align 1
@@ -56,10 +56,28 @@
   ret i32 %res
 }
 
+; CHECK-LABEL: test_signext_b_ult_slt
+; CHECK: ldrb [[LDR:r[0-9]+]], [r0]
+; CHECK: uxtab [[ADD:r[0-9]+]], [[LDR]], r1
+; CHECK: uxtb [[UXT:r[0-9]+]], r1
+; CHECK: cmp [[ADD]], [[UXT]]
+; CHECK: uxtb [[TRUNC:r[0-9]+]], [[ADD]]
+; CHECK: cmp [[TRUNC]], #127
+define i32 @test_signext_b_ult_slt(i8* %ptr, i8 signext %arg) {
+entry:
+  %0 = load i8, i8* %ptr, align 1
+  %1 = add nuw nsw i8 %0, %arg
+  %cmp = icmp sle i8 %1, 126
+  %cmp.1 = icmp ule i8 %1, %arg
+  %or = and i1 %cmp, %cmp.1
+  %res = select i1 %or, i32 42, i32 57
+  ret i32 %res
+}
+
 ; CHECK-LABEL: test_signext_h
 ; CHECK: ldrh [[LDR:r[0-9]+]], [r0]
-; CHECK: sxth [[SXT:r[0-9]+]], [[LDR]]
-; CHECK: cm{{.*}} [[SXT]]
+; CHECK: uxtah [[ADD:r[0-9]+]], [[LDR]], r1
+; CHECK: cm{{.*}} [[ADD]],
 define i32 @test_signext_h(i16* %ptr, i16 signext %arg) {
 entry:
   %0 = load i16, i16* %ptr, align 1
@@ -68,3 +86,4 @@
   %res = select i1 %cmp, i32 42, i32 20894
   ret i32 %res
 }
+