Revert r155136 "Defer some shl transforms to DAGCombine."

While the patch was perfect and defect free, it exposed a really nasty
bug in X86 SelectionDAG that caused an llc crash when compiling lencod.

I'll put the patch back in after fixing the SelectionDAG problem.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@155181 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 52 deletions

diff --git a/test/Transforms/InstCombine/shift.ll b/test/Transforms/InstCombine/shift.ll
index 25e708b7f5..52310e34e0 100644
--- a/test/Transforms/InstCombine/shift.ll
+++ b/test/Transforms/InstCombine/shift.ll
@@ -65,17 +65,8 @@ define i32 @test6(i32 %A) {
 ; CHECK: @test6
 ; CHECK-NEXT: mul i32 %A, 6
 ; CHECK-NEXT: ret i32
-        %B = shl i32 %A, 1      ;; convert to an mul instruction
-        %C = mul i32 %B, 3
-        ret i32 %C
-}
-
-define i32 @test6a(i32 %A) {
-; CHECK: @test6a
-; CHECK-NEXT: mul i32 %A, 6
-; CHECK-NEXT: ret i32
-        %B = mul i32 %A, 3
-        %C = shl i32 %B, 1      ;; convert to an mul instruction
+        %B = shl i32 %A, 1      ;; convert to an mul instruction 
+        %C = mul i32 %B, 3             
         ret i32 %C
 }
 
@@ -106,9 +97,7 @@ define i8 @test9(i8 %A) {
         ret i8 %C
 }
 
-;; This transformation is deferred to DAGCombine:
 ;; (A >> 7) << 7 === A & 128
-;; The shl may be valuable to scalar evolution.
 define i8 @test10(i8 %A) {
 ; CHECK: @test10
 ; CHECK-NEXT: and i8 %A, -128
@@ -118,21 +107,11 @@ define i8 @test10(i8 %A) {
         ret i8 %C
 }
 
-;; Allow the simplification when the lshr shift is exact.
-define i8 @test10a(i8 %A) {
-; CHECK: @test10a
-; CHECK-NEXT: ret i8 %A
-        %B = lshr exact i8 %A, 7
-        %C = shl i8 %B, 7
-        ret i8 %C
-}
-
-;; This transformation is deferred to DAGCombine:
 ;; (A >> 3) << 4 === (A & 0x1F) << 1
-;; The shl may be valuable to scalar evolution.
 define i8 @test11(i8 %A) {
 ; CHECK: @test11
-; CHECK: shl i8
+; CHECK-NEXT: mul i8 %A, 6
+; CHECK-NEXT: and i8
 ; CHECK-NEXT: ret i8
         %a = mul i8 %A, 3               ; <i8> [#uses=1]
         %B = lshr i8 %a, 3              ; <i8> [#uses=1]
@@ -140,18 +119,6 @@ define i8 @test11(i8 %A) {
         ret i8 %C
 }
 
-;; Allow the simplification in InstCombine when the lshr shift is exact.
-define i8 @test11a(i8 %A) {
-; CHECK: @test11a
-; CHECK-NEXT: mul i8 %A, 6
-; CHECK-NEXT: ret i8
-        %a = mul i8 %A, 3
-        %B = lshr exact i8 %a, 3
-        %C = shl i8 %B, 4
-        ret i8 %C
-}
-
-;; This is deferred to DAGCombine unless %B is single-use.
 ;; (A >> 8) << 8 === A & -256
 define i32 @test12(i32 %A) {
 ; CHECK: @test12
@@ -162,12 +129,11 @@ define i32 @test12(i32 %A) {
         ret i32 %C
 }
 
-;; This transformation is deferred to DAGCombine:
 ;; (A >> 3) << 4 === (A & -8) * 2
-;; The shl may be valuable to scalar evolution.
 define i8 @test13(i8 %A) {
 ; CHECK: @test13
-; CHECK: shl i8
+; CHECK-NEXT: mul i8 %A, 6
+; CHECK-NEXT: and i8
 ; CHECK-NEXT: ret i8
         %a = mul i8 %A, 3               ; <i8> [#uses=1]
         %B = ashr i8 %a, 3              ; <i8> [#uses=1]
@@ -175,16 +141,6 @@ define i8 @test13(i8 %A) {
         ret i8 %C
 }
 
-define i8 @test13a(i8 %A) {
-; CHECK: @test13a
-; CHECK-NEXT: mul i8 %A, 6
-; CHECK-NEXT: ret i8
-        %a = mul i8 %A, 3
-        %B = ashr exact i8 %a, 3
-        %C = shl i8 %B, 4
-        ret i8 %C
-}
-
 ;; D = ((B | 1234) << 4) === ((B << 4)|(1234 << 4)
 define i32 @test14(i32 %A) {
 ; CHECK: @test14
@@ -521,11 +477,10 @@ entry:
   %tmp49 = lshr i8 %tmp48, 5
   %tmp50 = mul i8 %tmp49, 64
   %tmp51 = xor i8 %tmp50, %tmp5
+; CHECK: and i8 %0, 16
   %tmp52 = and i8 %tmp51, -128
   %tmp53 = lshr i8 %tmp52, 7
-; CHECK: lshr i8 %tmp51, 7
   %tmp54 = mul i8 %tmp53, 16
-; CHECK: shl nuw nsw i8 %tmp53, 4
   %tmp55 = xor i8 %tmp54, %tmp51
 ; CHECK: ret i8 %tmp551
   ret i8 %tmp55