[InstCombine][CodeGenPrep] Create llvm.uadd.with.overflow in CGP.

Summary:
This change moves creating calls to `llvm.uadd.with.overflow` from
InstCombine to CodeGenPrep.  Combining overflow check patterns into
calls to the said intrinsic in InstCombine inhibits optimization because
it introduces an intrinsic call that not all other transforms and
analyses understand.

Depends on D8888.

Reviewers: majnemer, atrick

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D8889

llvm-svn: 234638

1 files changed, 5 insertions, 22 deletions

diff --git a/llvm/test/CodeGen/X86/add-of-carry.ll b/llvm/test/CodeGen/X86/add-of-carry.ll
index 9c24be4289f..44b587af3aa 100644
--- a/llvm/test/CodeGen/X86/add-of-carry.ll
+++ b/llvm/test/CodeGen/X86/add-of-carry.ll
@@ -4,43 +4,26 @@
 define i32 @test1(i32 %sum, i32 %x) nounwind readnone ssp {
 entry:
 ; CHECK-LABEL: test1:
-; CHECK: cmpl %ecx, %eax 
-; CHECK-NOT: addl
-; CHECK: adcl $0, %eax
-  %add4 = add i32 %x, %sum
-  %cmp = icmp ult i32 %add4, %x
-  %inc = zext i1 %cmp to i32
-  %z.0 = add i32 %add4, %inc
-  ret i32 %z.0
-}
-
-; Instcombine transforms test1 into test2:
-; CHECK-LABEL: test2:
 ; CHECK: movl
 ; CHECK-NEXT: addl
 ; CHECK-NEXT: adcl $0
 ; CHECK-NEXT: ret
-define i32 @test2(i32 %sum, i32 %x) nounwind readnone ssp {
-entry:
-  %uadd = call { i32, i1 } @llvm.uadd.with.overflow.i32(i32 %x, i32 %sum)
-  %0 = extractvalue { i32, i1 } %uadd, 0
-  %cmp = extractvalue { i32, i1 } %uadd, 1
+  %add4 = add i32 %x, %sum
+  %cmp = icmp ult i32 %add4, %x
   %inc = zext i1 %cmp to i32
-  %z.0 = add i32 %0, %inc
+  %z.0 = add i32 %add4, %inc
   ret i32 %z.0
 }
 
 ; <rdar://problem/12579915>
-define i32 @test3(i32 %x, i32 %y, i32 %res) nounwind uwtable readnone ssp {
+define i32 @test2(i32 %x, i32 %y, i32 %res) nounwind uwtable readnone ssp {
 entry:
   %cmp = icmp ugt i32 %x, %y
   %dec = sext i1 %cmp to i32
   %dec.res = add nsw i32 %dec, %res
   ret i32 %dec.res
-; CHECK-LABEL: test3:
+; CHECK-LABEL: test2:
 ; CHECK: cmpl
 ; CHECK: sbbl
 ; CHECK: ret
 }
-
-declare { i32, i1 } @llvm.uadd.with.overflow.i32(i32, i32) nounwind readnone