Index: llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
===================================================================
--- llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ llvm/trunk/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -3025,7 +3025,10 @@
       }
 
       // For example, "testl %eax, $32776" to "testw %ax, $32776".
-      if (isUInt<16>(Mask) && N0.getValueType() != MVT::i16 &&
+      // NOTE: We only want to form TESTW instructions if optimizing for
+      // min size. Otherwise we only save one byte and possibly get a length
+      // changing prefix penalty in the decoders.
+      if (OptForMinSize && isUInt<16>(Mask) && N0.getValueType() != MVT::i16 &&
           (!(Mask & 0x8000) || hasNoSignedComparisonUses(Node))) {
         SDValue Imm = CurDAG->getTargetConstant(Mask, dl, MVT::i16);
         SDValue Reg = N0.getOperand(0);
Index: llvm/trunk/test/CodeGen/X86/tbm_patterns.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/tbm_patterns.ll
+++ llvm/trunk/test/CodeGen/X86/tbm_patterns.ll
@@ -53,7 +53,7 @@
 ; CHECK-LABEL: test_x86_tbm_bextri_u32_z2:
 ; CHECK:       # BB#0:
 ; CHECK-NEXT:    shrl $4, %edi
-; CHECK-NEXT:    testw $4095, %di # imm = 0xFFF
+; CHECK-NEXT:    testl $4095, %edi # imm = 0xFFF
 ; CHECK-NEXT:    cmovnel %edx, %esi
 ; CHECK-NEXT:    movl %esi, %eax
 ; CHECK-NEXT:    retq
@@ -114,7 +114,7 @@
 ; CHECK-LABEL: test_x86_tbm_bextri_u64_z2:
 ; CHECK:       # BB#0:
 ; CHECK-NEXT:    shrl $4, %edi
-; CHECK-NEXT:    testw $4095, %di # imm = 0xFFF
+; CHECK-NEXT:    testl $4095, %edi # imm = 0xFFF
 ; CHECK-NEXT:    cmovneq %rdx, %rsi
 ; CHECK-NEXT:    movq %rsi, %rax
 ; CHECK-NEXT:    retq
Index: llvm/trunk/test/CodeGen/X86/test-shrink-bug.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/test-shrink-bug.ll
+++ llvm/trunk/test/CodeGen/X86/test-shrink-bug.ll
@@ -3,7 +3,7 @@
 ; Codegen shouldn't reduce the comparison down to testb $-1, %al
 ; because that changes the result of the signed test.
 ; PR5132
-; CHECK: testw  $255, %ax
+; CHECK: testl  $255, %eax
 
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
 target triple = "i386-apple-darwin10.0"
Index: llvm/trunk/test/CodeGen/X86/test-shrink.ll
===================================================================
--- llvm/trunk/test/CodeGen/X86/test-shrink.ll
+++ llvm/trunk/test/CodeGen/X86/test-shrink.ll
@@ -105,10 +105,10 @@
   ret void
 }
 ; CHECK-64-LABEL: g64x16:
-; CHECK-64:   testw $-32640, %[[A0W:di|cx]]
+; CHECK-64:   testl $32896, %[[A0D:edi|ecx]]
 ; CHECK-64:   ret
 ; CHECK-32-LABEL: g64x16:
-; CHECK-32:   testw $-32640, %ax
+; CHECK-32:   testl $32896, %eax
 ; CHECK-32:   ret
 define void @g64x16(i64 inreg %x) nounwind {
   %t = and i64 %x, 32896
@@ -121,11 +121,28 @@
 no:
   ret void
 }
+; CHECK-64-LABEL: g64x16minsize:
+; CHECK-64:   testw $-32640, %[[A0W:di|cx]]
+; CHECK-64:   ret
+; CHECK-32-LABEL: g64x16minsize:
+; CHECK-32:   testw $-32640, %ax
+; CHECK-32:   ret
+define void @g64x16minsize(i64 inreg %x) nounwind minsize {
+  %t = and i64 %x, 32896
+  %s = icmp eq i64 %t, 0
+  br i1 %s, label %yes, label %no
+
+yes:
+  call void @bar()
+  ret void
+no:
+  ret void
+}
 ; CHECK-64-LABEL: g32x16:
-; CHECK-64:   testw $-32640, %[[A0W]]
+; CHECK-64:   testl $32896, %[[A0D]]
 ; CHECK-64:   ret
 ; CHECK-32-LABEL: g32x16:
-; CHECK-32:   testw $-32640, %ax
+; CHECK-32:   testl $32896, %eax
 ; CHECK-32:   ret
 define void @g32x16(i32 inreg %x) nounwind {
   %t = and i32 %x, 32896
@@ -138,8 +155,25 @@
 no:
   ret void
 }
+; CHECK-64-LABEL: g32x16minsize:
+; CHECK-64:   testw $-32640, %[[A0W]]
+; CHECK-64:   ret
+; CHECK-32-LABEL: g32x16minsize:
+; CHECK-32:   testw $-32640, %ax
+; CHECK-32:   ret
+define void @g32x16minsize(i32 inreg %x) nounwind minsize {
+  %t = and i32 %x, 32896
+  %s = icmp eq i32 %t, 0
+  br i1 %s, label %yes, label %no
+
+yes:
+  call void @bar()
+  ret void
+no:
+  ret void
+}
 ; CHECK-64-LABEL: g64x32:
-; CHECK-64:   testl $268468352, %e[[A0W]]
+; CHECK-64:   testl $268468352, %[[A0D]]
 ; CHECK-64:   ret
 ; CHECK-32-LABEL: g64x32:
 ; CHECK-32:   testl $268468352, %eax