Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -17892,6 +17892,11 @@
   }
 
   if (AddTest) {
+    // Look past the AssertZext to see whether it is a truncate operation.
+    if (Cond.getOpcode() == ISD::AssertZext &&
+        Cond.getOperand(0).getOpcode() == ISD::TRUNCATE)
+      Cond = Cond.getOperand(0);
+
     // Look past the truncate if the high bits are known zero.
     if (isTruncWithZeroHighBitsInput(Cond, DAG))
       Cond = Cond.getOperand(0);
Index: test/CodeGen/X86/fp128-select.ll
===================================================================
--- test/CodeGen/X86/fp128-select.ll
+++ test/CodeGen/X86/fp128-select.ll
@@ -11,7 +11,7 @@
 define void @test_select(fp128* %p, fp128* %q, i1 zeroext %c) {
 ; MMX-LABEL: test_select:
 ; MMX:       # BB#0:
-; MMX-NEXT:    testb %dl, %dl
+; MMX-NEXT:    testl %edx, %edx
 ; MMX-NEXT:    jne .LBB0_1
 ; MMX-NEXT:  # BB#2:
 ; MMX-NEXT:    movaps {{.*}}(%rip), %xmm0
@@ -25,7 +25,7 @@
 ; CHECK-LABEL: test_select:
 ; CHECK:       # BB#0:
 ; CHECK-NEXT:    xorl %eax, %eax
-; CHECK-NEXT:    testb %dl, %dl
+; CHECK-NEXT:    testl %edx, %edx
 ; CHECK-NEXT:    cmovneq (%rdi), %rax
 ; CHECK-NEXT:    movabsq $9223231299366420480, %rcx # imm = 0x7FFF800000000000
 ; CHECK-NEXT:    cmovneq 8(%rdi), %rcx
Index: test/CodeGen/X86/select_const.ll
===================================================================
--- test/CodeGen/X86/select_const.ll
+++ test/CodeGen/X86/select_const.ll
@@ -413,7 +413,7 @@
 define i32 @select_C1_C2_zeroext(i1 zeroext %cond) {
 ; CHECK-LABEL: select_C1_C2_zeroext:
 ; CHECK:       # BB#0:
-; CHECK-NEXT:    testb %dil, %dil
+; CHECK-NEXT:    testl %edi, %edi
 ; CHECK-NEXT:    movl $421, %ecx # imm = 0x1A5
 ; CHECK-NEXT:    movl $42, %eax
 ; CHECK-NEXT:    cmovnel %ecx, %eax