commit f9d2b20daff1251bb53b02a7e12ba20324da106f
author Sanjay Patel <spatel@rotateright.com> Sat Jul 16 15:20:19 2016 +0000
committer Sanjay Patel <spatel@rotateright.com> Sat Jul 16 15:20:19 2016 +0000
tree 2e3bf9a65eb7a23a7b8c31e09ab32738e9059cac
parent ee0e63804f2aeb0e129ebc6d9c897e91ca979a3f

[InstCombine] reassociate logic ops with constants separated by a zext

This is a partial implementation of a general fold for associative+commutative operators:
(op (cast (op X, C2)), C1) --> (cast (op X, op (C1, C2)))
(op (cast (op X, C2)), C1) --> (op (cast X), op (C1, C2))

There are 7 associative operators and 13 cast types, so this could potentially go a lot further.

Differential Revision: https://reviews.llvm.org/D22421

llvm-svn: 275684

llvm/test/Transforms/InstCombine/assoc-cast-assoc.ll

diff --git a/llvm/test/Transforms/InstCombine/assoc-cast-assoc.ll b/llvm/test/Transforms/InstCombine/assoc-cast-assoc.ll
index ee19311..e410fde 100644
--- a/llvm/test/Transforms/InstCombine/assoc-cast-assoc.ll
+++ b/llvm/test/Transforms/InstCombine/assoc-cast-assoc.ll
@@ -3,9 +3,8 @@
 
 define i5 @XorZextXor(i3 %a) {
 ; CHECK-LABEL: @XorZextXor(
-; CHECK-NEXT:    [[OP1:%.*]] = xor i3 %a, 3
-; CHECK-NEXT:    [[CAST:%.*]] = zext i3 [[OP1]] to i5
-; CHECK-NEXT:    [[OP2:%.*]] = xor i5 [[CAST]], 12
+; CHECK-NEXT:    [[CAST:%.*]] = zext i3 %a to i5
+; CHECK-NEXT:    [[OP2:%.*]] = xor i5 [[CAST]], 15
 ; CHECK-NEXT:    ret i5 [[OP2]]
 ;
   %op1 = xor i3 %a, 3
@@ -16,9 +15,8 @@
 
 define <2 x i32> @XorZextXorVec(<2 x i1> %a) {
 ; CHECK-LABEL: @XorZextXorVec(
-; CHECK-NEXT:    [[OP1:%.*]] = xor <2 x i1> %a, <i1 true, i1 false>
-; CHECK-NEXT:    [[CAST:%.*]] = zext <2 x i1> [[OP1]] to <2 x i32>
-; CHECK-NEXT:    [[OP2:%.*]] = xor <2 x i32> [[CAST]], <i32 3, i32 1>
+; CHECK-NEXT:    [[CAST:%.*]] = zext <2 x i1> %a to <2 x i32>
+; CHECK-NEXT:    [[OP2:%.*]] = xor <2 x i32> [[CAST]], <i32 2, i32 1>
 ; CHECK-NEXT:    ret <2 x i32> [[OP2]]
 ;
   %op1 = xor <2 x i1> %a, <i1 true, i1 false>
@@ -29,9 +27,8 @@
 
 define i5 @OrZextOr(i3 %a) {
 ; CHECK-LABEL: @OrZextOr(
-; CHECK-NEXT:    [[OP1:%.*]] = or i3 %a, 3
-; CHECK-NEXT:    [[CAST:%.*]] = zext i3 [[OP1]] to i5
-; CHECK-NEXT:    [[OP2:%.*]] = or i5 [[CAST]], 8
+; CHECK-NEXT:    [[CAST:%.*]] = zext i3 %a to i5
+; CHECK-NEXT:    [[OP2:%.*]] = or i5 [[CAST]], 11
 ; CHECK-NEXT:    ret i5 [[OP2]]
 ;
   %op1 = or i3 %a, 3
@@ -42,9 +39,8 @@
 
 define <2 x i32> @OrZextOrVec(<2 x i2> %a) {
 ; CHECK-LABEL: @OrZextOrVec(
-; CHECK-NEXT:    [[OP1:%.*]] = or <2 x i2> %a, <i2 -2, i2 0>
-; CHECK-NEXT:    [[CAST:%.*]] = zext <2 x i2> [[OP1]] to <2 x i32>
-; CHECK-NEXT:    [[OP2:%.*]] = or <2 x i32> [[CAST]], <i32 1, i32 5>
+; CHECK-NEXT:    [[CAST:%.*]] = zext <2 x i2> %a to <2 x i32>
+; CHECK-NEXT:    [[OP2:%.*]] = or <2 x i32> [[CAST]], <i32 3, i32 5>
 ; CHECK-NEXT:    ret <2 x i32> [[OP2]]
 ;
   %op1 = or <2 x i2> %a, <i2 2, i2 0>
@@ -69,9 +65,8 @@
 
 define <2 x i32> @AndZextAndVec(<2 x i8> %a) {
 ; CHECK-LABEL: @AndZextAndVec(
-; CHECK-NEXT:    [[OP1:%.*]] = and <2 x i8> %a, <i8 7, i8 0>
-; CHECK-NEXT:    [[CAST:%.*]] = zext <2 x i8> [[OP1]] to <2 x i32>
-; CHECK-NEXT:    [[OP2:%.*]] = and <2 x i32> [[CAST]], <i32 261, i32 1>
+; CHECK-NEXT:    [[CAST:%.*]] = zext <2 x i8> %a to <2 x i32>
+; CHECK-NEXT:    [[OP2:%.*]] = and <2 x i32> [[CAST]], <i32 5, i32 0>
 ; CHECK-NEXT:    ret <2 x i32> [[OP2]]
 ;
   %op1 = and <2 x i8> %a, <i8 7, i8 0>