[llvm] [ValueTracking] Compute knownbits from `(icmp upred (add/sub nuw X, Y), C)` (PR #87180)
Nikita Popov via llvm-commits
llvm-commits at lists.llvm.org
Wed May 15 20:30:09 PDT 2024
================
@@ -1374,5 +1374,226 @@ define i8 @nonzero_reduce_xor_vscale_odd(<vscale x 3 x i8> %xx) {
ret i8 %r
}
+define i8 @test_icmp_add(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_add(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_ADD:%.*]] = add nuw i8 [[N:%.*]], [[N2:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i8 [[N_ADD]], 32
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: ret i8 0
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+;
+entry:
+ %n_add = add nuw i8 %n, %n2
+ %cmp = icmp ult i8 %n_add, 32
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ %r = and i8 %n, 32
+ ret i8 %r
+
+if.else:
+ ret i8 %other
+}
+
+define i8 @test_icmp_add2(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_add2(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_ADD:%.*]] = add nuw i8 [[N:%.*]], [[N2:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 [[N_ADD]], 14
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 0
+;
+entry:
+ %n_add = add nuw i8 %n, %n2
+ %cmp = icmp uge i8 %n_add, 15
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ ret i8 %other
+if.else:
+ %r = and i8 %n, 32
+ ret i8 %r
+
+}
+
+define i8 @test_icmp_add_fail_bad_range(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_add_fail_bad_range(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_ADD:%.*]] = add nuw i8 [[N:%.*]], [[N2:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i8 [[N_ADD]], 33
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: [[R:%.*]] = and i8 [[N]], 32
+; CHECK-NEXT: ret i8 [[R]]
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+;
+entry:
+ %n_add = add nuw i8 %n, %n2
+ %cmp = icmp ule i8 %n_add, 32
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ %r = and i8 %n, 32
+ ret i8 %r
+
+if.else:
+ ret i8 %other
+}
+
+define i8 @test_icmp_add_fail_bad_pred(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_add_fail_bad_pred(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_ADD:%.*]] = add nuw i8 [[N:%.*]], [[N2:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 [[N_ADD]], 32
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: [[R:%.*]] = and i8 [[N]], 32
+; CHECK-NEXT: ret i8 [[R]]
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+;
+entry:
+ %n_add = add nuw i8 %n, %n2
+ %cmp = icmp ugt i8 %n_add, 32
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ %r = and i8 %n, 32
+ ret i8 %r
+
+if.else:
+ ret i8 %other
+}
+
+define i8 @test_icmp_sub(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_sub(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_AND:%.*]] = sub nuw i8 [[N:%.*]], [[N2:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 [[N_AND]], -33
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: ret i8 32
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+;
+entry:
+ %n_sub = sub nuw i8 %n, %n2
+ %cmp = icmp ugt i8 %n_sub, 223
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ %r = and i8 %n, 32
+ ret i8 %r
+
+if.else:
+ ret i8 %other
+}
+
+define i8 @test_icmp_sub_fail_wrong_arg(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_sub_fail_wrong_arg(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_AND:%.*]] = sub nuw i8 [[N1:%.*]], [[N:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 [[N_AND]], -33
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: [[R:%.*]] = and i8 [[N]], 32
+; CHECK-NEXT: ret i8 [[R]]
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+;
+entry:
+ %n_sub = sub nuw i8 %n, %n2
+ %cmp = icmp ugt i8 %n_sub, 223
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ %r = and i8 %n2, 32
+ ret i8 %r
+
+if.else:
+ ret i8 %other
+}
+
+define i8 @test_icmp_sub2(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_sub2(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_SUB:%.*]] = sub nuw i8 [[N:%.*]], [[N2:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult i8 [[N_SUB]], -31
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 32
+;
+entry:
+ %n_sub = sub nuw i8 %n, %n2
+ %cmp = icmp ule i8 %n_sub, 224
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ ret i8 %other
+if.else:
+ %r = and i8 %n, 32
+ ret i8 %r
+
+}
+
+define i8 @test_icmp_sub_fail_bad_range(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_sub_fail_bad_range(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_SUB:%.*]] = sub nuw i8 [[N:%.*]], [[N2:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt i8 [[N_SUB]], -34
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: [[R:%.*]] = and i8 [[N]], 32
+; CHECK-NEXT: ret i8 [[R]]
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+;
+entry:
+ %n_sub = sub nuw i8 %n, %n2
+ %cmp = icmp uge i8 %n_sub, 223
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ %r = and i8 %n, 32
+ ret i8 %r
+
+if.else:
+ ret i8 %other
+}
+
+define i8 @test_icmp_sub_fail_bad_pred(i8 %n, i8 %n2, i8 %other) {
+; CHECK-LABEL: @test_icmp_sub_fail_bad_pred(
+; CHECK-NEXT: entry:
+; CHECK-NEXT: [[N_SUB:%.*]] = sub nuw i8 [[N:%.*]], [[N2:%.*]]
+; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i8 [[N_SUB]], 31
+; CHECK-NEXT: br i1 [[CMP]], label [[IF_THEN:%.*]], label [[IF_ELSE:%.*]]
+; CHECK: if.then:
+; CHECK-NEXT: [[R:%.*]] = and i8 [[N]], 32
+; CHECK-NEXT: ret i8 [[R]]
+; CHECK: if.else:
+; CHECK-NEXT: ret i8 [[OTHER:%.*]]
+;
+entry:
+ %n_sub = sub nuw i8 %n, %n2
+ %cmp = icmp sge i8 %n_sub, 32
+ br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+ %r = and i8 %n, 32
+ ret i8 %r
+
+if.else:
+ ret i8 %other
+}
----------------
nikic wrote:
Negative tests without nuw?
https://github.com/llvm/llvm-project/pull/87180
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