[InstCombine] Pull shifts through a select plus binop with constant

This pulls shifts through a select+binop with a constant where the select conditionally executes the binop. We already do this for just the binop, but not with the select.

This can allow us to get the select closer to other selects to enable removing one.

Differential Revision: https://reviews.llvm.org/D39222

llvm-svn: 317510

1 files changed, 260 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/shift.ll b/llvm/test/Transforms/InstCombine/shift.ll
index cbb3d614db2..ba52023e0db 100644
--- a/llvm/test/Transforms/InstCombine/shift.ll
+++ b/llvm/test/Transforms/InstCombine/shift.ll
@@ -1332,3 +1332,263 @@ define i7 @test65(i7 %a, i7 %b) {
   %y = and i7 %x, 1 ; this extracts the lsb which should be 0 because we shifted an even number of bits and all even bits of the shift input are 0.
   ret i7 %y
 }
+
+define i32 @shl_select_add_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shl_select_add_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[TMP1]], 14
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = add i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = shl i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @shl_select_add_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shl_select_add_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[TMP1]], 14
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = add i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = shl i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @shl_select_and_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shl_select_and_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP1]], 14
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = and i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = shl i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @shl_select_and_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shl_select_and_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP1]], 14
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = and i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = shl i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @lshr_select_and_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @lshr_select_and_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = and i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = lshr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @lshr_select_and_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @lshr_select_and_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = and i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = lshr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @ashr_select_and_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @ashr_select_and_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = ashr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP1]], -1073741821
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = and i32 %x, 2147483655
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = ashr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @ashr_select_and_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @ashr_select_and_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = ashr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = and i32 [[TMP1]], -1073741821
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = and i32 %x, 2147483655
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = ashr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @shl_select_or_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shl_select_or_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = or i32 [[TMP1]], 14
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = or i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = shl i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @shl_select_or_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shl_select_or_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = or i32 [[TMP1]], 14
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = or i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = shl i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @lshr_select_or_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @lshr_select_or_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = or i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = or i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = lshr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @lshr_select_or_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @lshr_select_or_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = or i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = or i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = lshr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @ashr_select_or_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @ashr_select_or_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = ashr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = or i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = or i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = ashr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @ashr_select_or_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @ashr_select_or_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = ashr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = or i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = or i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = ashr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @shl_select_xor_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shl_select_xor_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], 14
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = xor i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = shl i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @shl_select_xor_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @shl_select_xor_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = shl i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], 14
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = xor i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = shl i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @lshr_select_xor_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @lshr_select_xor_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = xor i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = lshr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @lshr_select_xor_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @lshr_select_xor_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = xor i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = lshr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @ashr_select_xor_true(i32 %x, i1 %cond) {
+; CHECK-LABEL: @ashr_select_xor_true(
+; CHECK-NEXT:    [[TMP1:%.*]] = ashr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP2]], i32 [[TMP1]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = xor i32 %x, 7
+  %2 = select i1 %cond, i32 %1, i32 %x
+  %3 = ashr i32 %2, 1
+  ret i32 %3
+}
+
+define i32 @ashr_select_xor_false(i32 %x, i1 %cond) {
+; CHECK-LABEL: @ashr_select_xor_false(
+; CHECK-NEXT:    [[TMP1:%.*]] = ashr i32 [[X:%.*]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = xor i32 [[TMP1]], 3
+; CHECK-NEXT:    [[TMP3:%.*]] = select i1 [[COND:%.*]], i32 [[TMP1]], i32 [[TMP2]]
+; CHECK-NEXT:    ret i32 [[TMP3]]
+;
+  %1 = xor i32 %x, 7
+  %2 = select i1 %cond, i32 %x, i32 %1
+  %3 = ashr i32 %2, 1
+  ret i32 %3
+}