rdar://12329730 (2nd part)

 This change tries to simmplify E1 = " X >> C1 << C2" into :
  - E2 = "X << (C2 - C1)" if C2 > C1, or
  - E2 = "X >> (C1 - C2)" if C1 > C2, or
  - E2 = X if C1 == C2.

 Reviewed by Nadav. Thanks!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@169182 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 80 insertions, 4 deletions

diff --git a/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll b/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll
index eb28994..5efad8a 100644
--- a/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll
+++ b/test/Transforms/InstCombine/2010-11-01-lshr-mask.ll
@@ -5,8 +5,8 @@
 define i32 @main(i32 %argc) nounwind ssp {
 entry:
   %tmp3151 = trunc i32 %argc to i8
-; CHECK: %tmp3163 = shl i8 %tmp3162, 6
-; CHECK: and i8 %tmp3163, 64
+; CHECK: %tmp3162 = shl i8 %tmp3151, 5
+; CHECK: and i8 %tmp3162, 64
 ; CHECK-NOT: shl
 ; CHECK-NOT: shr
   %tmp3161 = or i8 %tmp3151, -17
diff --git a/test/Transforms/InstCombine/shift.ll b/test/Transforms/InstCombine/shift.ll
index 25e708b..b152816 100644
--- a/test/Transforms/InstCombine/shift.ll
+++ b/test/Transforms/InstCombine/shift.ll
@@ -659,3 +659,79 @@ define i32 @test53(i32 %x) {
 ; CHECK-NEXT: %B = shl nuw i32 %x, 2
 ; CHECK-NEXT: ret i32 %B
 }
+
+define i32 @test54(i32 %x) {
+  %shr2 = lshr i32 %x, 1
+  %shl = shl i32 %shr2, 4
+  %and = and i32 %shl, 16
+  ret i32 %and
+; CHECK: @test54
+; CHECK: shl i32 %x, 3
+}
+
+
+define i32 @test55(i32 %x) {
+  %shr2 = lshr i32 %x, 1
+  %shl = shl i32 %shr2, 4
+  %or = or i32 %shl, 8
+  ret i32 %or
+; CHECK: @test55
+; CHECK: shl i32 %x, 3
+}
+
+define i32 @test56(i32 %x) {
+  %shr2 = lshr i32 %x, 1
+  %shl = shl i32 %shr2, 4
+  %or = or i32 %shl, 7
+  ret i32 %or
+; CHECK: @test56
+; CHECK: shl i32 %shr2, 4
+}
+
+
+define i32 @test57(i32 %x) {
+  %shr = lshr i32 %x, 1
+  %shl = shl i32 %shr, 4
+  %and = and i32 %shl, 16
+  ret i32 %and
+; CHECK: @test57
+; CHECK: shl i32 %x, 3
+}
+
+define i32 @test58(i32 %x) {
+  %shr = lshr i32 %x, 1
+  %shl = shl i32 %shr, 4
+  %or = or i32 %shl, 8
+  ret i32 %or
+; CHECK: @test58
+; CHECK: shl i32 %x, 3
+}
+
+define i32 @test59(i32 %x) {
+  %shr = ashr i32 %x, 1
+  %shl = shl i32 %shr, 4
+  %or = or i32 %shl, 7
+  ret i32 %or
+; CHECK: @test59
+; CHECK: %shl = shl i32 %shr1, 4
+}
+
+
+define i32 @test60(i32 %x) {
+  %shr = ashr i32 %x, 4
+  %shl = shl i32 %shr, 1
+  %or = or i32 %shl, 1
+  ret i32 %or
+; CHECK: @test60
+; CHECK: lshr i32 %x, 3
+}
+
+
+define i32 @test61(i32 %x) {
+  %shr = ashr i32 %x, 4
+  %shl = shl i32 %shr, 1
+  %or = or i32 %shl, 2
+  ret i32 %or
+; CHECK: @test61
+; CHECK: ashr i32 %x, 4
+}
diff --git a/test/Transforms/InstCombine/signext.ll b/test/Transforms/InstCombine/signext.ll
index ecee983..5ed1cd5 100644
--- a/test/Transforms/InstCombine/signext.ll
+++ b/test/Transforms/InstCombine/signext.ll
@@ -82,6 +82,6 @@ entry:
   %sub = add i32 %xor, -67108864                  ; <i32> [#uses=1]
   ret i32 %sub
 ; CHECK: @test8
-; CHECK: %shr = ashr i32 %x, 5
-; CHECK: ret i32 %shr
+; CHECK: %sub = ashr i32 %x, 5
+; CHECK: ret i32 %sub
 }