[ValueTracking] Add test for assume with trunc as argument (NFC)

Author: andjo403

llvm/test/Transforms/InstSimplify/assume-non-zero.ll

@@ -231,3 +231,17 @@ define i1 @nonnull17_unknown(i8 %x) {
   %q = icmp ne i8 %x, 0
   ret i1 %q
 }
+
+define i1 @nonnull_trunc_true(i8 %x) {
+; CHECK-LABEL: @nonnull_trunc_true(
+; CHECK-NEXT:    [[A:%.*]] = trunc i8 [[X:%.*]] to i1
+; CHECK-NEXT:    call void @llvm.assume(i1 [[A]])
+; CHECK-NEXT:    [[Q:%.*]] = icmp ne i8 [[X]], 0
+; CHECK-NEXT:    ret i1 [[Q]]
+;
+  %a = trunc i8 %x to i1
+  call void @llvm.assume(i1 %a)
+  %q = icmp ne i8 %x, 0
+  ret i1 %q
+}
+

llvm/test/Transforms/InstSimplify/compare.ll

@@ -3424,6 +3424,21 @@ define i1 @icmp_ult_vscale_false(i8 %x, i8 %y) {
   ret i1 %cmp
 }
 
+define i1 @icmp_eq_false_by_trunc(i8 %x) {
+; CHECK-LABEL: @icmp_eq_false_by_trunc(
+; CHECK-NEXT:    [[TRUNC:%.*]] = trunc i8 [[X:%.*]] to i1
+; CHECK-NEXT:    [[NOT:%.*]] = xor i1 [[TRUNC]], true
+; CHECK-NEXT:    call void @llvm.assume(i1 [[NOT]])
+; CHECK-NEXT:    [[CMP:%.*]] = icmp eq i8 [[X]], 1
+; CHECK-NEXT:    ret i1 [[CMP]]
+;
+  %trunc = trunc i8 %x to i1
+  %not = xor i1 %trunc, true
+  call void @llvm.assume(i1 %not)
+  %cmp = icmp eq i8 %x, 1
+  ret i1 %cmp
+}
+
 declare i64 @llvm.vscale.i64()
 
 ; TODO: Add coverage for global aliases, link once, etc..

llvm/test/Transforms/InstSimplify/shr-nop.ll

@@ -381,6 +381,19 @@ define i32 @exact_lshr_lowbit(i32 %shiftval) {
   ret i32 %shr
 }
 
+define i8 @exact_lshr_lowbit_set_assume_trunc(i8 %x) {
+; CHECK-LABEL: @exact_lshr_lowbit_set_assume_trunc(
+; CHECK-NEXT:    [[COND:%.*]] = trunc i8 [[X:%.*]] to i1
+; CHECK-NEXT:    call void @llvm.assume(i1 [[COND]])
+; CHECK-NEXT:    [[SHR:%.*]] = lshr exact i8 [[X]], 1
+; CHECK-NEXT:    ret i8 [[SHR]]
+;
+  %cond = trunc i8 %x to i1
+  call void @llvm.assume(i1 %cond)
+  %shr = lshr exact i8 %x, 1
+  ret i8 %shr
+}
+
 define i32 @exact_ashr_lowbit(i32 %shiftval) {
 ; CHECK-LABEL: @exact_ashr_lowbit(
 ; CHECK-NEXT:    ret i32 7