[ValueTracking] Add tests for knownbits of saturating add/sub functions; NFC

Reviewed By: RKSimon

Differential Revision: https://reviews.llvm.org/D150101

diff --git a/llvm/test/Analysis/ValueTracking/knownbits-sat-addsub.ll b/llvm/test/Analysis/ValueTracking/knownbits-sat-addsub.ll
new file mode 100644 (file)
index 0000000..47e4adc
--- /dev/null
+++ b/llvm/test/Analysis/ValueTracking/knownbits-sat-addsub.ll
@@ -0,0 +1,219 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=instsimplify -S < %s | FileCheck %s
+
+declare i8 @llvm.sadd.sat.i8(i8, i8)
+declare i8 @llvm.ssub.sat.i8(i8, i8)
+declare i8 @llvm.uadd.sat.i8(i8, i8)
+declare i8 @llvm.usub.sat.i8(i8, i8)
+
+define i1 @uadd_sat_overflow(i8 %x, i8 %y) {
+; CHECK-LABEL: @uadd_sat_overflow(
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[X:%.*]], -128
+; CHECK-NEXT:    [[RHS:%.*]] = or i8 [[Y:%.*]], -128
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.uadd.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[EXP]], -2
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %lhs = or i8 %x, 128
+  %rhs = or i8 %y, 128
+  %exp = call i8 @llvm.uadd.sat.i8(i8 %lhs, i8 %rhs)
+  %r = icmp eq i8 %exp, 254
+  ret i1 %r
+}
+
+define i1 @uadd_sat_overflow_fail(i8 %x, i8 %y) {
+; CHECK-LABEL: @uadd_sat_overflow_fail(
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[X:%.*]], -128
+; CHECK-NEXT:    [[RHS:%.*]] = or i8 [[Y:%.*]], 126
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.uadd.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[EXP]], -2
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %lhs = or i8 %x, 128
+  %rhs = or i8 %y, 126
+  %exp = call i8 @llvm.uadd.sat.i8(i8 %lhs, i8 %rhs)
+  %r = icmp eq i8 %exp, 254
+  ret i1 %r
+}
+
+define i1 @usub_sat_overflow(i8 %x, i8 %y) {
+; CHECK-LABEL: @usub_sat_overflow(
+; CHECK-NEXT:    [[LHS:%.*]] = and i8 [[X:%.*]], 127
+; CHECK-NEXT:    [[RHS:%.*]] = or i8 [[Y:%.*]], -128
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.usub.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[EXP]], 1
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %lhs = and i8 %x, 127
+  %rhs = or i8 %y, 128
+  %exp = call i8 @llvm.usub.sat.i8(i8 %lhs, i8 %rhs)
+  %r = icmp eq i8 %exp, 1
+  ret i1 %r
+}
+
+define i1 @usub_sat_overflow_fail(i8 %x, i8 %y) {
+; CHECK-LABEL: @usub_sat_overflow_fail(
+; CHECK-NEXT:    [[LHS:%.*]] = and i8 [[X:%.*]], 127
+; CHECK-NEXT:    [[RHS:%.*]] = or i8 [[Y:%.*]], 126
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.usub.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[EXP]], 1
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %lhs = and i8 %x, 127
+  %rhs = or i8 %y, 126
+  %exp = call i8 @llvm.usub.sat.i8(i8 %lhs, i8 %rhs)
+  %r = icmp eq i8 %exp, 1
+  ret i1 %r
+}
+
+define i1 @sadd_sat_overflow_pos(i8 %x, i8 %y) {
+; CHECK-LABEL: @sadd_sat_overflow_pos(
+; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], 127
+; CHECK-NEXT:    [[YY:%.*]] = and i8 [[Y:%.*]], 127
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[XX]], 64
+; CHECK-NEXT:    [[RHS:%.*]] = or i8 [[YY]], 65
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.sadd.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[EXP]], -128
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %xx = and i8 %x, 127
+  %yy = and i8 %y, 127
+  %lhs = or i8 %xx, 64
+  %rhs = or i8 %yy, 65
+  %exp = call i8 @llvm.sadd.sat.i8(i8 %lhs, i8 %rhs)
+  %r = icmp eq i8 %exp, 128
+  ret i1 %r
+}
+
+define i1 @sadd_sat_low_bits(i8 %x, i8 %y) {
+; CHECK-LABEL: @sadd_sat_low_bits(
+; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], 15
+; CHECK-NEXT:    [[YY:%.*]] = and i8 [[Y:%.*]], 15
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[XX]], 1
+; CHECK-NEXT:    [[RHS:%.*]] = and i8 [[YY]], -2
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.sadd.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[EXP]], 1
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 0
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %xx = and i8 %x, 15
+  %yy = and i8 %y, 15
+  %lhs = or i8 %xx, 1
+  %rhs = and i8 %yy, -2
+  %exp = call i8 @llvm.sadd.sat.i8(i8 %lhs, i8 %rhs)
+  %and = and i8 %exp, 1
+  %r = icmp eq i8 %and, 0
+  ret i1 %r
+}
+
+define i1 @sadd_sat_fail_may_overflow(i8 %x, i8 %y) {
+; CHECK-LABEL: @sadd_sat_fail_may_overflow(
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[X:%.*]], 1
+; CHECK-NEXT:    [[RHS:%.*]] = and i8 [[Y:%.*]], -2
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.sadd.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[EXP]], 1
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 0
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %lhs = or i8 %x, 1
+  %rhs = and i8 %y, -2
+  %exp = call i8 @llvm.sadd.sat.i8(i8 %lhs, i8 %rhs)
+  %and = and i8 %exp, 1
+  %r = icmp eq i8 %and, 0
+  ret i1 %r
+}
+
+define i1 @sadd_sat_overflow_neg(i8 %x, i8 %y) {
+; CHECK-LABEL: @sadd_sat_overflow_neg(
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[X:%.*]], -64
+; CHECK-NEXT:    [[RHS:%.*]] = or i8 [[Y:%.*]], -65
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.sadd.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[EXP]], 127
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %lhs = or i8 %x, 192
+  %rhs = or i8 %y, 191
+  %exp = call i8 @llvm.sadd.sat.i8(i8 %lhs, i8 %rhs)
+  %r = icmp eq i8 %exp, 127
+  ret i1 %r
+}
+
+define i1 @ssub_sat_overflow_neg(i8 %x, i8 %y) {
+; CHECK-LABEL: @ssub_sat_overflow_neg(
+; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], 112
+; CHECK-NEXT:    [[YY:%.*]] = and i8 [[Y:%.*]], 127
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[XX]], -128
+; CHECK-NEXT:    [[RHS:%.*]] = or i8 [[YY]], 126
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.ssub.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[EXP]], 32
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %xx = and i8 %x, 112
+  %yy = and i8 %y, 127
+  %lhs = or i8 %xx, 128
+  %rhs = or i8 %yy, 126
+  %exp = call i8 @llvm.ssub.sat.i8(i8 %lhs, i8 %rhs)
+  %r = icmp eq i8 %exp, 32
+  ret i1 %r
+}
+
+define i1 @ssub_sat_low_bits(i8 %x, i8 %y) {
+; CHECK-LABEL: @ssub_sat_low_bits(
+; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], 15
+; CHECK-NEXT:    [[YY:%.*]] = and i8 [[Y:%.*]], 15
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[XX]], 17
+; CHECK-NEXT:    [[RHS:%.*]] = and i8 [[YY]], -2
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.ssub.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[EXP]], 1
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 0
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %xx = and i8 %x, 15
+  %yy = and i8 %y, 15
+  %lhs = or i8 %xx, 17
+  %rhs = and i8 %yy, -2
+  %exp = call i8 @llvm.ssub.sat.i8(i8 %lhs, i8 %rhs)
+  %and = and i8 %exp, 1
+  %r = icmp eq i8 %and, 0
+  ret i1 %r
+}
+
+define i1 @ssub_sat_fail_may_overflow(i8 %x, i8 %y) {
+; CHECK-LABEL: @ssub_sat_fail_may_overflow(
+; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], 15
+; CHECK-NEXT:    [[YY:%.*]] = and i8 [[Y:%.*]], 15
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[XX]], 1
+; CHECK-NEXT:    [[RHS:%.*]] = and i8 [[YY]], -2
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.ssub.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[AND:%.*]] = and i8 [[EXP]], 1
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[AND]], 0
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %xx = and i8 %x, 15
+  %yy = and i8 %y, 15
+  %lhs = or i8 %xx, 1
+  %rhs = and i8 %yy, -2
+  %exp = call i8 @llvm.ssub.sat.i8(i8 %lhs, i8 %rhs)
+  %and = and i8 %exp, 1
+  %r = icmp eq i8 %and, 0
+  ret i1 %r
+}
+
+define i1 @ssub_sat_overflow_pos(i8 %x, i8 %y) {
+; CHECK-LABEL: @ssub_sat_overflow_pos(
+; CHECK-NEXT:    [[XX:%.*]] = and i8 [[X:%.*]], 24
+; CHECK-NEXT:    [[YY:%.*]] = and i8 [[Y:%.*]], 3
+; CHECK-NEXT:    [[LHS:%.*]] = or i8 [[XX]], 8
+; CHECK-NEXT:    [[RHS:%.*]] = or i8 [[YY]], -128
+; CHECK-NEXT:    [[EXP:%.*]] = call i8 @llvm.ssub.sat.i8(i8 [[LHS]], i8 [[RHS]])
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[EXP]], -128
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %xx = and i8 %x, 24
+  %yy = and i8 %y, 3
+  %lhs = or i8 %xx, 8
+  %rhs = or i8 %yy, 128
+  %exp = call i8 @llvm.ssub.sat.i8(i8 %lhs, i8 %rhs)
+  %r = icmp eq i8 %exp, 128
+  ret i1 %r
+}