Refactored and updated SimplifyUsingDistributiveLaws() to

 * Find factorization opportunities using identity values.
 * Find factorization opportunities by treating shl(X, C) as mul (X, shl(C))
 * Keep NSW flag while simplifying instruction using factorization.

This fixes PR19263.

Differential Revision: http://reviews.llvm.org/D3799

llvm-svn: 211261

1 files changed, 68 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/add2.ll b/llvm/test/Transforms/InstCombine/add2.ll
index aaf3a7a235b..c728b4437af 100644
--- a/llvm/test/Transforms/InstCombine/add2.ll
+++ b/llvm/test/Transforms/InstCombine/add2.ll
@@ -86,3 +86,71 @@ define i16 @test9(i16 %a) {
 ; CHECK-NEXT:  %d = mul i16 %a, -32767
 ; CHECK-NEXT:  ret i16 %d
 }
+
+define i16 @add_nsw_mul_nsw(i16 %x) {
+ %add1 = add nsw i16 %x, %x
+ %add2 = add nsw i16 %add1, %x
+ ret i16 %add2
+; CHECK-LABEL: @add_nsw_mul_nsw(
+; CHECK-NEXT: %add2 = mul nsw i16 %x, 3
+; CHECK-NEXT: ret i16 %add2
+}
+
+define i16 @mul_add_to_mul_1(i16 %x) {
+ %mul1 = mul nsw i16 %x, 8
+ %add2 = add nsw i16 %x, %mul1
+ ret i16 %add2
+; CHECK-LABEL: @mul_add_to_mul_1(
+; CHECK-NEXT: %add2 = mul nsw i16 %x, 9
+; CHECK-NEXT: ret i16 %add2
+}
+
+define i16 @mul_add_to_mul_2(i16 %x) {
+ %mul1 = mul nsw i16 %x, 8
+ %add2 = add nsw i16 %mul1, %x
+ ret i16 %add2
+; CHECK-LABEL: @mul_add_to_mul_2(
+; CHECK-NEXT: %add2 = mul nsw i16 %x, 9
+; CHECK-NEXT: ret i16 %add2
+}
+
+define i16 @mul_add_to_mul_3(i16 %a) {
+ %mul1 = mul i16 %a, 2
+ %mul2 = mul i16 %a, 3
+ %add = add nsw i16 %mul1, %mul2
+ ret i16 %add
+; CHECK-LABEL: @mul_add_to_mul_3(
+; CHECK-NEXT: %add = mul i16 %a, 5
+; CHECK-NEXT: ret i16 %add
+}
+
+define i16 @mul_add_to_mul_4(i16 %a) {
+ %mul1 = mul nsw i16 %a, 2
+ %mul2 = mul nsw i16 %a, 7
+ %add = add nsw i16 %mul1, %mul2
+ ret i16 %add
+; CHECK-LABEL: @mul_add_to_mul_4(
+; CHECK-NEXT: %add = mul nsw i16 %a, 9
+; CHECK-NEXT: ret i16 %add
+}
+
+define i16 @mul_add_to_mul_5(i16 %a) {
+ %mul1 = mul nsw i16 %a, 3
+ %mul2 = mul nsw i16 %a, 7
+ %add = add nsw i16 %mul1, %mul2
+ ret i16 %add
+; CHECK-LABEL: @mul_add_to_mul_5(
+; CHECK-NEXT: %add = mul nsw i16 %a, 10
+; CHECK-NEXT: ret i16 %add
+}
+
+define i32 @mul_add_to_mul_6(i32 %x, i32 %y) {
+  %mul1 = mul nsw i32 %x, %y
+  %mul2 = mul nsw i32 %mul1, 5
+  %add = add nsw i32 %mul1, %mul2
+  ret i32 %add
+; CHECK-LABEL: @mul_add_to_mul_6(
+; CHECK-NEXT: %mul1 = mul nsw i32 %x, %y
+; CHECK-NEXT: %add = mul nsw i32 %mul1, 6
+; CHECK-NEXT: ret i32 %add
+}