ValueTracking/test: increase recurrence coverage

[artagnon]

The shift-recurrence-knownbits.ll test file only covers shift instructions while testing recurrence patterns with knownbits. Add tests for add, sub, mul, and, and or as well, and rename the file recurrence-knownbits.ll.

[llvmbot]

@llvm/pr-subscribers-llvm-analysis

Author: Ramkumar Ramachandra (artagnon)

Changes

The shift-recurrence-knownbits.ll test file only covers shift instructions while testing recurrence patterns with knownbits. Add tests for add, sub, mul, and, and or as well, and rename the file recurrence-knownbits.ll.

---

Full diff: https://github.com/llvm/llvm-project/pull/108836.diff

1 Files Affected:

• (renamed) llvm/test/Analysis/ValueTracking/recurrence-knownbits.ll (+100)

diff --git a/llvm/test/Analysis/ValueTracking/shift-recurrence-knownbits.ll b/llvm/test/Analysis/ValueTracking/recurrence-knownbits.ll
similarity index 65%
rename from llvm/test/Analysis/ValueTracking/shift-recurrence-knownbits.ll
rename to llvm/test/Analysis/ValueTracking/recurrence-knownbits.ll
index 5e9084aac31a38..3355328cad9ecf 100644
--- a/llvm/test/Analysis/ValueTracking/shift-recurrence-knownbits.ll
+++ b/llvm/test/Analysis/ValueTracking/recurrence-knownbits.ll
@@ -21,6 +21,106 @@ exit:
   ret i64 %res
 }
 
+define i64 @test_add(i1 %c) {
+; CHECK-LABEL: @test_add(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i64 0
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [8, %entry], [%iv.next, %loop]
+  %iv.next = add nuw i64 %iv, 4
+  br i1 %c, label %exit, label %loop
+exit:
+  %res = and i64 %iv, 1
+  ret i64 %res
+}
+
+define i64 @test_sub(i1 %c) {
+; CHECK-LABEL: @test_sub(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i64 0
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [8, %entry], [%iv.next, %loop]
+  %iv.next = sub nuw i64 %iv, 4
+  br i1 %c, label %exit, label %loop
+exit:
+  %res = and i64 %iv, 1
+  ret i64 %res
+}
+
+define i64 @test_mul(i1 %c) {
+; CHECK-LABEL: @test_mul(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i64 0
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [8, %entry], [%iv.next, %loop]
+  %iv.next = mul i64 %iv, 2
+  br i1 %c, label %exit, label %loop
+exit:
+  %res = and i64 %iv, 2
+  ret i64 %res
+}
+
+define i64 @test_and(i1 %c) {
+; CHECK-LABEL: @test_and(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i64 2047
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [1025, %entry], [%iv.next, %loop]
+  %iv.next = and i64 %iv, 1024
+  br i1 %c, label %exit, label %loop
+exit:
+  %res = or i64 %iv, 1023
+  ret i64 %res
+}
+
+define i64 @test_or(i1 %c) {
+; CHECK-LABEL: @test_or(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[LOOP:%.*]]
+; CHECK:       loop:
+; CHECK-NEXT:    br i1 [[C:%.*]], label [[EXIT:%.*]], label [[LOOP]]
+; CHECK:       exit:
+; CHECK-NEXT:    ret i64 2047
+;
+entry:
+  br label %loop
+loop:
+  %iv = phi i64 [1025, %entry], [%iv.next, %loop]
+  %iv.next = or i64 %iv, 1024
+  br i1 %c, label %exit, label %loop
+exit:
+  %res = or i64 %iv, 1023
+  ret i64 %res
+}
+
 define i64 @test_ashr_zeros(i1 %c) {
 ; CHECK-LABEL: @test_ashr_zeros(
 ; CHECK-NEXT:  entry:

[nikic]

LGTM, but I didn't try to confirm that the tests are not present elsewhere (a way to do that is to comment out the relevant cases and run tests...)

[artagnon]

I didn't try to confirm that the tests are not present elsewhere (a way to do that is to comment out the relevant cases and run tests...)

I did that part of course, and there is some existing but scattered coverage that isn't reduced: I thought it would be good to have a collection of tests testing the recurrence patterns in one place, as a prelude to adding support for other BinOps. Note that although the switch statement has support for FMul, it is impossible to test, as (I think) KnownBits doesn't work with fp values.