ValueTracking: Recognize fcmp ole/ugt with inf as a class test

[arsenm]

These were missed and hopefully avoids assertions when dc3faf0 is recommitted.

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

@llvm/pr-subscribers-llvm-analysis

Author: Matt Arsenault (arsenm)

Changes

These were missed and hopefully avoids assertions when dc3faf0 is recommitted.

---

Full diff: https://github.com/llvm/llvm-project/pull/79095.diff

2 Files Affected:

• (modified) llvm/lib/Analysis/ValueTracking.cpp (+16-2)
• (modified) llvm/test/Transforms/Attributor/nofpclass-implied-by-fcmp.ll (+14-16)

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 34d501032098888..5f880e8694dc7a5 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -4065,7 +4065,7 @@ llvm::fcmpToClassTest(FCmpInst::Predicate Pred, const Function &F, Value *LHS,
     case FCmpInst::FCMP_ULE: // isnan(x) || x <= 0
       return {LHS, fcNegative | fcPosZero | fcNan};
     default:
-      break;
+      llvm_unreachable("all compare types are handled");
     }
 
     return {nullptr, fcAllFlags};
@@ -4184,8 +4184,22 @@ llvm::fcmpToClassTest(FCmpInst::Predicate Pred, const Function &F, Value *LHS,
       Mask = fcNone;
       break;
     }
+    case FCmpInst::FCMP_OLE:
+    case FCmpInst::FCMP_UGT: {
+      if (ConstRHS->isNegative()) {
+        Mask = fcNone;
+        break;
+      }
+
+      // fcmp ole x, +inf -> fcmp ord x, x
+      // fcmp ole fabs(x), +inf -> fcmp ord x, x
+      // fcmp ole x, -inf -> false
+      // fcmp ole fabs(x), -inf -> false
+      Mask = ~fcNan;
+      break;
+    }
     default:
-      return {nullptr, fcAllFlags};
+      llvm_unreachable("all compare types are handled");
     }
   } else if (ConstRHS->isSmallestNormalized() && !ConstRHS->isNegative()) {
     // Match pattern that's used in __builtin_isnormal.
diff --git a/llvm/test/Transforms/Attributor/nofpclass-implied-by-fcmp.ll b/llvm/test/Transforms/Attributor/nofpclass-implied-by-fcmp.ll
index ccd01de458c3c4d..54b879ee1dea741 100644
--- a/llvm/test/Transforms/Attributor/nofpclass-implied-by-fcmp.ll
+++ b/llvm/test/Transforms/Attributor/nofpclass-implied-by-fcmp.ll
@@ -2400,8 +2400,8 @@ define float @assume_oeq_smallest_normal_known_pos(float nofpclass(ninf nsub nno
 ;---------------------------------------------------------------------
 
 define float @assume_ole_pinf(float %arg) {
-; CHECK-LABEL: define float @assume_ole_pinf(
-; CHECK-SAME: float returned [[ARG:%.*]]) #[[ATTR3]] {
+; CHECK-LABEL: define nofpclass(nan) float @assume_ole_pinf(
+; CHECK-SAME: float returned nofpclass(nan) [[ARG:%.*]]) #[[ATTR3]] {
 ; CHECK-NEXT:    [[FCMP:%.*]] = fcmp ole float [[ARG]], 0x7FF0000000000000
 ; CHECK-NEXT:    call void @llvm.assume(i1 noundef [[FCMP]]) #[[ATTR5]]
 ; CHECK-NEXT:    ret float [[ARG]]
@@ -2412,10 +2412,9 @@ define float @assume_ole_pinf(float %arg) {
 }
 
 define float @assume_ole_ninf(float %arg) {
-; CHECK-LABEL: define float @assume_ole_ninf(
-; CHECK-SAME: float returned [[ARG:%.*]]) #[[ATTR3]] {
-; CHECK-NEXT:    [[FCMP:%.*]] = fcmp ole float [[ARG]], 0xFFF0000000000000
-; CHECK-NEXT:    call void @llvm.assume(i1 noundef [[FCMP]]) #[[ATTR5]]
+; CHECK-LABEL: define nofpclass(all) float @assume_ole_ninf(
+; CHECK-SAME: float returned nofpclass(all) [[ARG:%.*]]) #[[ATTR3]] {
+; CHECK-NEXT:    call void @llvm.assume(i1 noundef false) #[[ATTR5]]
 ; CHECK-NEXT:    ret float [[ARG]]
 ;
   %fcmp = fcmp ole float %arg, 0xFFF0000000000000
@@ -2424,8 +2423,8 @@ define float @assume_ole_ninf(float %arg) {
 }
 
 define float @assume_ugt_pinf(float %arg) {
-; CHECK-LABEL: define float @assume_ugt_pinf(
-; CHECK-SAME: float returned [[ARG:%.*]]) #[[ATTR3]] {
+; CHECK-LABEL: define nofpclass(inf zero sub norm) float @assume_ugt_pinf(
+; CHECK-SAME: float returned nofpclass(inf zero sub norm) [[ARG:%.*]]) #[[ATTR3]] {
 ; CHECK-NEXT:    [[FCMP:%.*]] = fcmp ugt float [[ARG]], 0x7FF0000000000000
 ; CHECK-NEXT:    call void @llvm.assume(i1 noundef [[FCMP]]) #[[ATTR5]]
 ; CHECK-NEXT:    ret float [[ARG]]
@@ -2438,8 +2437,7 @@ define float @assume_ugt_pinf(float %arg) {
 define float @assume_ugt_ninf(float %arg) {
 ; CHECK-LABEL: define float @assume_ugt_ninf(
 ; CHECK-SAME: float returned [[ARG:%.*]]) #[[ATTR3]] {
-; CHECK-NEXT:    [[FCMP:%.*]] = fcmp ugt float [[ARG]], 0xFFF0000000000000
-; CHECK-NEXT:    call void @llvm.assume(i1 noundef [[FCMP]]) #[[ATTR5]]
+; CHECK-NEXT:    call void @llvm.assume(i1 noundef true) #[[ATTR5]]
 ; CHECK-NEXT:    ret float [[ARG]]
 ;
   %fcmp = fcmp ugt float %arg, 0xFFF0000000000000
@@ -2448,8 +2446,8 @@ define float @assume_ugt_ninf(float %arg) {
 }
 
 define float @assume_fabs_ole_pinf(float %arg) {
-; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @assume_fabs_ole_pinf(
-; CHECK-SAME: float returned nofpclass(ninf nzero nsub nnorm) [[ARG:%.*]]) #[[ATTR3]] {
+; CHECK-LABEL: define nofpclass(nan ninf nzero nsub nnorm) float @assume_fabs_ole_pinf(
+; CHECK-SAME: float returned nofpclass(nan ninf nzero nsub nnorm) [[ARG:%.*]]) #[[ATTR3]] {
 ; CHECK-NEXT:    [[FABS:%.*]] = call float @llvm.fabs.f32(float [[ARG]]) #[[ATTR4]]
 ; CHECK-NEXT:    [[FCMP:%.*]] = fcmp ole float [[FABS]], 0x7FF0000000000000
 ; CHECK-NEXT:    call void @llvm.assume(i1 noundef [[FCMP]]) #[[ATTR5]]
@@ -2462,8 +2460,8 @@ define float @assume_fabs_ole_pinf(float %arg) {
 }
 
 define float @assume_fabs_ole_ninf(float %arg) {
-; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @assume_fabs_ole_ninf(
-; CHECK-SAME: float returned nofpclass(ninf nzero nsub nnorm) [[ARG:%.*]]) #[[ATTR3]] {
+; CHECK-LABEL: define nofpclass(all) float @assume_fabs_ole_ninf(
+; CHECK-SAME: float returned nofpclass(all) [[ARG:%.*]]) #[[ATTR3]] {
 ; CHECK-NEXT:    call void @llvm.assume(i1 noundef false) #[[ATTR5]]
 ; CHECK-NEXT:    ret float [[ARG]]
 ;
@@ -2474,8 +2472,8 @@ define float @assume_fabs_ole_ninf(float %arg) {
 }
 
 define float @assume_fabs_ugt_pinf(float %arg) {
-; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @assume_fabs_ugt_pinf(
-; CHECK-SAME: float returned nofpclass(ninf nzero nsub nnorm) [[ARG:%.*]]) #[[ATTR3]] {
+; CHECK-LABEL: define nofpclass(inf zero sub norm) float @assume_fabs_ugt_pinf(
+; CHECK-SAME: float returned nofpclass(inf zero sub norm) [[ARG:%.*]]) #[[ATTR3]] {
 ; CHECK-NEXT:    [[FABS:%.*]] = call float @llvm.fabs.f32(float [[ARG]]) #[[ATTR4]]
 ; CHECK-NEXT:    [[FCMP:%.*]] = fcmp ugt float [[FABS]], 0x7FF0000000000000
 ; CHECK-NEXT:    call void @llvm.assume(i1 noundef [[FCMP]]) #[[ATTR5]]

[jayfoad]

fcNegInf, surely?

[jayfoad]

LGTM.