[DAGCombiner] Push truncate through adde when the carry isn't used.

Summary: As per title.

Reviewers: mkuper, spatel, bkramer, RKSimon, zvi

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D29528

llvm-svn: 294394
diff --git a/llvm/test/CodeGen/X86/adde-carry.ll b/llvm/test/CodeGen/X86/adde-carry.ll
index e111f68..9483a6b 100644
--- a/llvm/test/CodeGen/X86/adde-carry.ll
+++ b/llvm/test/CodeGen/X86/adde-carry.ll
@@ -28,8 +28,7 @@
 ; CHECK-LABEL: b:
 ; CHECK:       # BB#0: # %entry
 ; CHECK-NEXT:    addq %rdx, %rsi
-; CHECK-NEXT:    sbbq %rax, %rax
-; CHECK-NEXT:    subl %eax, %ecx
+; CHECK-NEXT:    adcl $0, %ecx
 ; CHECK-NEXT:    movl %ecx, (%rdi)
 ; CHECK-NEXT:    retq
 entry:
@@ -48,8 +47,7 @@
 ; CHECK-LABEL: c:
 ; CHECK:       # BB#0: # %entry
 ; CHECK-NEXT:    addq %rdx, %rsi
-; CHECK-NEXT:    sbbq %rax, %rax
-; CHECK-NEXT:    subl %eax, %ecx
+; CHECK-NEXT:    adcl $0, %ecx
 ; CHECK-NEXT:    movw %cx, (%rdi)
 ; CHECK-NEXT:    retq
 entry:
@@ -68,8 +66,7 @@
 ; CHECK-LABEL: d:
 ; CHECK:       # BB#0: # %entry
 ; CHECK-NEXT:    addq %rdx, %rsi
-; CHECK-NEXT:    sbbq %rax, %rax
-; CHECK-NEXT:    subl %eax, %ecx
+; CHECK-NEXT:    adcl $0, %ecx
 ; CHECK-NEXT:    movb %cl, (%rdi)
 ; CHECK-NEXT:    retq
 entry:
@@ -165,8 +162,8 @@
 ; CHECK-NEXT:    adcq $0, %rdx
 ; CHECK-NEXT:    movq %rax, (%rdi)
 ; CHECK-NEXT:    addq 8(%rdi), %rdx
-; CHECK-NEXT:    sbbq %rax, %rax
 ; CHECK-NEXT:    movq %rdx, 8(%rdi)
+; CHECK-NEXT:    sbbl %eax, %eax
 ; CHECK-NEXT:    subl %eax, 16(%rdi)
 ; CHECK-NEXT:    retq
 entry:
diff --git a/llvm/test/CodeGen/X86/known-bits.ll b/llvm/test/CodeGen/X86/known-bits.ll
index f3fa127..e458d7ab 100644
--- a/llvm/test/CodeGen/X86/known-bits.ll
+++ b/llvm/test/CodeGen/X86/known-bits.ll
@@ -151,8 +151,7 @@
 ; X64-NEXT:    andq $-1024, %rdi # imm = 0xFC00
 ; X64-NEXT:    andq $-1024, %rsi # imm = 0xFC00
 ; X64-NEXT:    addq %rdi, %rsi
-; X64-NEXT:    sbbq %rax, %rax
-; X64-NEXT:    subl %eax, %edx
+; X64-NEXT:    adcl $0, %edx
 ; X64-NEXT:    shldq $54, %rsi, %rdx
 ; X64-NEXT:    xorl %eax, %eax
 ; X64-NEXT:    retq