[llvm] goldsteinn/known vec reverse (PR #99013)
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Tue Jul 16 03:16:40 PDT 2024
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-llvm-analysis
Author: None (goldsteinn)
<details>
<summary>Changes</summary>
- **[ValueTracking] Add tests for Known{Bits,NonZero,FPClass} for `llvm.vector.reverse`; NFC**
- **[ValueTracking] Implement Known{Bits,NonZero,FPClass} for `llvm.vector.reverse`**
---
Full diff: https://github.com/llvm/llvm-project/pull/99013.diff
4 Files Affected:
- (modified) llvm/lib/Analysis/ValueTracking.cpp (+9)
- (added) llvm/test/Analysis/ValueTracking/known-bits.ll (+25)
- (added) llvm/test/Analysis/ValueTracking/known-fpclass.ll (+26)
- (modified) llvm/test/Analysis/ValueTracking/known-non-zero.ll (+23)
``````````diff
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 7be8a18dd7271..7cc2c2e5ebcb5 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1684,6 +1684,8 @@ static void computeKnownBitsFromOperator(const Operator *I,
computeKnownBits(I->getOperand(1), Known2, Depth + 1, Q);
Known = KnownBits::ssub_sat(Known, Known2);
break;
+ // Vec reverse preserves bits from input vec.
+ case Intrinsic::vector_reverse:
// for min/max/and/or reduce, any bit common to each element in the
// input vec is set in the output.
case Intrinsic::vector_reduce_and:
@@ -3026,6 +3028,8 @@ static bool isKnownNonZeroFromOperator(const Operator *I,
return isNonZeroAdd(DemandedElts, Depth, Q, BitWidth,
II->getArgOperand(0), II->getArgOperand(1),
/*NSW=*/true, /* NUW=*/false);
+ // Vec reverse preserves zero/non-zero status from input vec.
+ case Intrinsic::vector_reverse:
// umin/smin/smax/smin/or of all non-zero elements is always non-zero.
case Intrinsic::vector_reduce_or:
case Intrinsic::vector_reduce_umax:
@@ -5163,6 +5167,11 @@ void computeKnownFPClass(const Value *V, const APInt &DemandedElts,
Known.SignBit.reset();
break;
}
+ // reverse preserves all characteristics of the input vec's element.
+ case Intrinsic::vector_reverse:
+ Known = computeKnownFPClass(II->getArgOperand(0), II->getFastMathFlags(),
+ InterestedClasses, Depth + 1, Q);
+ break;
case Intrinsic::trunc:
case Intrinsic::floor:
case Intrinsic::ceil:
diff --git a/llvm/test/Analysis/ValueTracking/known-bits.ll b/llvm/test/Analysis/ValueTracking/known-bits.ll
new file mode 100644
index 0000000000000..035ccf8d42d13
--- /dev/null
+++ b/llvm/test/Analysis/ValueTracking/known-bits.ll
@@ -0,0 +1,25 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=instsimplify < %s -S | FileCheck %s
+
+define <4 x i1> @vec_reverse_known_bits(<4 x i8> %xx) {
+; CHECK-LABEL: @vec_reverse_known_bits(
+; CHECK-NEXT: ret <4 x i1> <i1 true, i1 true, i1 true, i1 true>
+;
+ %x = or <4 x i8> %xx, <i8 128, i8 128, i8 128, i8 128>
+ %rev = call <4 x i8> @llvm.vector.reverse(<4 x i8> %x)
+ %r = icmp slt <4 x i8> %rev, zeroinitializer
+ ret <4 x i1> %r
+}
+
+define <4 x i1> @vec_reverse_known_bits_fail(<4 x i8> %xx) {
+; CHECK-LABEL: @vec_reverse_known_bits_fail(
+; CHECK-NEXT: [[X:%.*]] = or <4 x i8> [[XX:%.*]], <i8 -128, i8 -128, i8 -128, i8 127>
+; CHECK-NEXT: [[REV:%.*]] = call <4 x i8> @llvm.vector.reverse.v4i8(<4 x i8> [[X]])
+; CHECK-NEXT: [[R:%.*]] = icmp slt <4 x i8> [[REV]], zeroinitializer
+; CHECK-NEXT: ret <4 x i1> [[R]]
+;
+ %x = or <4 x i8> %xx, <i8 128, i8 128, i8 128, i8 127>
+ %rev = call <4 x i8> @llvm.vector.reverse(<4 x i8> %x)
+ %r = icmp slt <4 x i8> %rev, zeroinitializer
+ ret <4 x i1> %r
+}
diff --git a/llvm/test/Analysis/ValueTracking/known-fpclass.ll b/llvm/test/Analysis/ValueTracking/known-fpclass.ll
new file mode 100644
index 0000000000000..59f3eed715b52
--- /dev/null
+++ b/llvm/test/Analysis/ValueTracking/known-fpclass.ll
@@ -0,0 +1,26 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt -passes=instsimplify < %s -S | FileCheck %s
+
+define <4 x i1> @vector_reverse_fpclass(<4 x double> nofpclass(nzero nan) %x) {
+; CHECK-LABEL: @vector_reverse_fpclass(
+; CHECK-NEXT: ret <4 x i1> <i1 true, i1 true, i1 true, i1 true>
+;
+ %x.abs = call <4 x double> @llvm.fabs.v4f64(<4 x double> %x)
+ %op = call <4 x double> @llvm.vector.reverse(<4 x double> %x.abs)
+ %cmp = fcmp oge <4 x double> %op, <double 0.0, double 0.0, double 0.0, double 0.0>
+ ret <4 x i1> %cmp
+}
+
+define <4 x i1> @vector_reverse_fpclass2(<4 x double> nofpclass(nzero) %x) {
+; CHECK-LABEL: @vector_reverse_fpclass2(
+; CHECK-NEXT: [[X_ABS:%.*]] = call <4 x double> @llvm.fabs.v4f64(<4 x double> [[X:%.*]])
+; CHECK-NEXT: [[OP:%.*]] = call <4 x double> @llvm.vector.reverse.v4f64(<4 x double> [[X_ABS]])
+; CHECK-NEXT: [[CMP:%.*]] = fcmp oge <4 x double> [[OP]], zeroinitializer
+; CHECK-NEXT: ret <4 x i1> [[CMP]]
+;
+ %x.abs = call <4 x double> @llvm.fabs.v4f64(<4 x double> %x)
+ %op = call <4 x double> @llvm.vector.reverse(<4 x double> %x.abs)
+ %cmp = fcmp oge <4 x double> %op, <double 0.0, double 0.0, double 0.0, double 0.0>
+ ret <4 x i1> %cmp
+}
+
diff --git a/llvm/test/Analysis/ValueTracking/known-non-zero.ll b/llvm/test/Analysis/ValueTracking/known-non-zero.ll
index c00e47fba8c72..5704586d92300 100644
--- a/llvm/test/Analysis/ValueTracking/known-non-zero.ll
+++ b/llvm/test/Analysis/ValueTracking/known-non-zero.ll
@@ -1497,4 +1497,27 @@ define i1 @trunc_nsw_nuw_non_zero_fail(i8 %xx) {
ret i1 %r
}
+define <4 x i1> @vec_reverse_non_zero(<4 x i8> %xx) {
+; CHECK-LABEL: @vec_reverse_non_zero(
+; CHECK-NEXT: ret <4 x i1> zeroinitializer
+;
+ %x = add nuw <4 x i8> %xx, <i8 1, i8 1, i8 1, i8 1>
+ %rev = call <4 x i8> @llvm.vector.reverse(<4 x i8> %x)
+ %r = icmp eq <4 x i8> %rev, zeroinitializer
+ ret <4 x i1> %r
+}
+
+define <4 x i1> @vec_reverse_non_zero_fail(<4 x i8> %xx) {
+; CHECK-LABEL: @vec_reverse_non_zero_fail(
+; CHECK-NEXT: [[X:%.*]] = add nuw <4 x i8> [[XX:%.*]], <i8 1, i8 0, i8 1, i8 1>
+; CHECK-NEXT: [[REV:%.*]] = call <4 x i8> @llvm.vector.reverse.v4i8(<4 x i8> [[X]])
+; CHECK-NEXT: [[R:%.*]] = icmp eq <4 x i8> [[REV]], zeroinitializer
+; CHECK-NEXT: ret <4 x i1> [[R]]
+;
+ %x = add nuw <4 x i8> %xx, <i8 1, i8 0, i8 1, i8 1>
+ %rev = call <4 x i8> @llvm.vector.reverse(<4 x i8> %x)
+ %r = icmp eq <4 x i8> %rev, zeroinitializer
+ ret <4 x i1> %r
+}
+
declare i32 @llvm.experimental.get.vector.length.i32(i32, i32, i1)
``````````
</details>
https://github.com/llvm/llvm-project/pull/99013
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