[PATCH] D148563: ValueTracking: Implement computeKnownFPClass for fma/fmuladd

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added reviewers: jcranmer-intel, foad, kpn, sepavloff, andrew.w.kaylor.
Herald added subscribers: StephenFan, okura, kuter, hiraditya.
Herald added a project: All.
arsenm requested review of this revision.
Herald added a subscriber: wdng.
Herald added a reviewer: jdoerfert.
Herald added a reviewer: sstefan1.
Herald added a project: LLVM.

Copy handling from CannotBeOrderedLessThanZero


https://reviews.llvm.org/D148563

Files:
  llvm/lib/Analysis/ValueTracking.cpp
  llvm/test/Transforms/Attributor/nofpclass-fma.ll


Index: llvm/test/Transforms/Attributor/nofpclass-fma.ll
===================================================================
--- llvm/test/Transforms/Attributor/nofpclass-fma.ll
+++ llvm/test/Transforms/Attributor/nofpclass-fma.ll
@@ -15,9 +15,9 @@
 }
 
 define float @ret_fma_same_mul_arg_positive_addend(float %arg0, float nofpclass(ninf nsub nnorm) %arg1) {
-; CHECK-LABEL: define float @ret_fma_same_mul_arg_positive_addend
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_fma_same_mul_arg_positive_addend
 ; CHECK-SAME: (float [[ARG0:%.*]], float nofpclass(ninf nsub nnorm) [[ARG1:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.fma.f32(float [[ARG0]], float [[ARG0]], float [[ARG1]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.fma.f32(float [[ARG0]], float [[ARG0]], float [[ARG1]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.fma.f32(float %arg0, float %arg0, float %arg1)
@@ -35,9 +35,9 @@
 }
 
 define float @ret_fmuladd_different_same_arg_positive_addend(float %arg0, float nofpclass(ninf nsub nnorm) %arg1) {
-; CHECK-LABEL: define float @ret_fmuladd_different_same_arg_positive_addend
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @ret_fmuladd_different_same_arg_positive_addend
 ; CHECK-SAME: (float [[ARG0:%.*]], float nofpclass(ninf nsub nnorm) [[ARG1:%.*]]) #[[ATTR1]] {
-; CHECK-NEXT:    [[CALL:%.*]] = call float @llvm.fmuladd.f32(float [[ARG0]], float [[ARG0]], float [[ARG1]]) #[[ATTR2]]
+; CHECK-NEXT:    [[CALL:%.*]] = call nofpclass(ninf nzero nsub nnorm) float @llvm.fmuladd.f32(float [[ARG0]], float [[ARG0]], float [[ARG1]]) #[[ATTR2]]
 ; CHECK-NEXT:    ret float [[CALL]]
 ;
   %call = call float @llvm.fmuladd.f32(float %arg0, float %arg0, float %arg1)
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -4238,6 +4238,24 @@
 
         break;
       }
+      case Intrinsic::fma:
+      case Intrinsic::fmuladd: {
+        if ((InterestedClasses & fcNegative) == fcNone)
+          break;
+
+        if (II->getArgOperand(0) != II->getArgOperand(1))
+          break;
+
+        // x * x + y is non-negative if y is non-negative.
+        KnownFPClass KnownAddend;
+        computeKnownFPClass(II->getArgOperand(2), DemandedElts,
+                            InterestedClasses, KnownAddend, Depth + 1, Q, TLI);
+
+        // TODO: Known sign bit with no nans
+        if (KnownAddend.cannotBeOrderedLessThanZero())
+          Known.knownNot(fcNegative);
+        break;
+      }
       case Intrinsic::sin:
       case Intrinsic::cos: {
         // Return NaN on infinite inputs.


-------------- next part --------------
A non-text attachment was scrubbed...
Name: D148563.514374.patch
Type: text/x-patch
Size: 2791 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20230417/754ab724/attachment.bin>