[InstSimplify] Generalize simplifyAndOrOfFCmps to handle fabs (llvm#116590)

dtcxzyw · web-flow · commit 42ed77578351 · 2024-11-19T20:10:40.000+08:00
This patch generalizes llvm#81027 to handle pattern `and/or (fcmp ord/uno X, 0), (fcmp pred fabs(X), Y)`. Alive2: https://alive2.llvm.org/ce/z/tsgUrz The correctness is straightforward because `fcmp ord/uno X, 0.0` is equivalent to `fcmp ord/uno fabs(X), 0.0`. We may generalize it to handle fneg as well. Address comment llvm#116065 (review)
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1857,27 +1857,31 @@ static Value *simplifyAndOrOfFCmps(const SimplifyQuery &Q, FCmpInst *LHS,
     return nullptr;
 
   FCmpInst::Predicate PredL = LHS->getPredicate(), PredR = RHS->getPredicate();
+  auto AbsOrSelfLHS0 = m_CombineOr(m_Specific(LHS0), m_FAbs(m_Specific(LHS0)));
   if ((PredL == FCmpInst::FCMP_ORD || PredL == FCmpInst::FCMP_UNO) &&
       ((FCmpInst::isOrdered(PredR) && IsAnd) ||
        (FCmpInst::isUnordered(PredR) && !IsAnd))) {
-    // (fcmp ord X, 0) & (fcmp o** X, Y) --> fcmp o** X, Y
-    // (fcmp uno X, 0) & (fcmp o** X, Y) --> false
-    // (fcmp uno X, 0) | (fcmp u** X, Y) --> fcmp u** X, Y
-    // (fcmp ord X, 0) | (fcmp u** X, Y) --> true
-    if ((LHS0 == RHS0 || LHS0 == RHS1) && match(LHS1, m_PosZeroFP()))
+    // (fcmp ord X, 0) & (fcmp o** X/abs(X), Y) --> fcmp o** X/abs(X), Y
+    // (fcmp uno X, 0) & (fcmp o** X/abs(X), Y) --> false
+    // (fcmp uno X, 0) | (fcmp u** X/abs(X), Y) --> fcmp u** X/abs(X), Y
+    // (fcmp ord X, 0) | (fcmp u** X/abs(X), Y) --> true
+    if ((match(RHS0, AbsOrSelfLHS0) || match(RHS1, AbsOrSelfLHS0)) &&
+        match(LHS1, m_PosZeroFP()))
       return FCmpInst::isOrdered(PredL) == FCmpInst::isOrdered(PredR)
                  ? static_cast<Value *>(RHS)
                  : ConstantInt::getBool(LHS->getType(), !IsAnd);
   }
 
+  auto AbsOrSelfRHS0 = m_CombineOr(m_Specific(RHS0), m_FAbs(m_Specific(RHS0)));
   if ((PredR == FCmpInst::FCMP_ORD || PredR == FCmpInst::FCMP_UNO) &&
       ((FCmpInst::isOrdered(PredL) && IsAnd) ||
        (FCmpInst::isUnordered(PredL) && !IsAnd))) {
-    // (fcmp o** X, Y) & (fcmp ord X, 0) --> fcmp o** X, Y
-    // (fcmp o** X, Y) & (fcmp uno X, 0) --> false
-    // (fcmp u** X, Y) | (fcmp uno X, 0) --> fcmp u** X, Y
-    // (fcmp u** X, Y) | (fcmp ord X, 0) --> true
-    if ((RHS0 == LHS0 || RHS0 == LHS1) && match(RHS1, m_PosZeroFP()))
+    // (fcmp o** X/abs(X), Y) & (fcmp ord X, 0) --> fcmp o** X/abs(X), Y
+    // (fcmp o** X/abs(X), Y) & (fcmp uno X, 0) --> false
+    // (fcmp u** X/abs(X), Y) | (fcmp uno X, 0) --> fcmp u** X/abs(X), Y
+    // (fcmp u** X/abs(X), Y) | (fcmp ord X, 0) --> true
+    if ((match(LHS0, AbsOrSelfRHS0) || match(LHS1, AbsOrSelfRHS0)) &&
+        match(RHS1, m_PosZeroFP()))
       return FCmpInst::isOrdered(PredL) == FCmpInst::isOrdered(PredR)
                  ? static_cast<Value *>(LHS)
                  : ConstantInt::getBool(LHS->getType(), !IsAnd);
diff --git a/llvm/test/CodeGen/AMDGPU/fp-classify.ll b/llvm/test/CodeGen/AMDGPU/fp-classify.ll
@@ -698,12 +698,9 @@ define amdgpu_kernel void @test_isfinite_pattern_4_f16(ptr addrspace(1) nocaptur
 ; SI-NEXT:    s_mov_b32 s3, 0xf000
 ; SI-NEXT:    s_mov_b32 s2, -1
 ; SI-NEXT:    s_waitcnt lgkmcnt(0)
-; SI-NEXT:    v_cvt_f32_f16_e32 v0, s6
 ; SI-NEXT:    s_and_b32 s4, s6, 0x7fff
-; SI-NEXT:    v_cmp_o_f32_e32 vcc, v0, v0
 ; SI-NEXT:    s_cmpk_lt_i32 s4, 0x7c00
 ; SI-NEXT:    s_cselect_b64 s[4:5], -1, 0
-; SI-NEXT:    s_and_b64 s[4:5], vcc, s[4:5]
 ; SI-NEXT:    v_cndmask_b32_e64 v0, 0, 1, s[4:5]
 ; SI-NEXT:    buffer_store_dword v0, off, s[0:3], 0
 ; SI-NEXT:    s_endpgm
diff --git a/llvm/test/Transforms/InstCombine/create-class-from-logic-fcmp.ll b/llvm/test/Transforms/InstCombine/create-class-from-logic-fcmp.ll
@@ -990,7 +990,8 @@ define i1 @not_isnormalinf_or_inf(half %x) #0 {
 ; -> subnormal | zero | nan
 define i1 @not_isnormalinf_or_uno(half %x) #0 {
 ; CHECK-LABEL: @not_isnormalinf_or_uno(
-; CHECK-NEXT:    [[OR:%.*]] = call i1 @llvm.is.fpclass.f16(half [[X:%.*]], i32 243)
+; CHECK-NEXT:    [[FABS:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
+; CHECK-NEXT:    [[OR:%.*]] = fcmp ult half [[FABS]], 0xH0400
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %fabs = call half @llvm.fabs.f16(half %x)
@@ -1003,7 +1004,8 @@ define i1 @not_isnormalinf_or_uno(half %x) #0 {
 ; -> subnormal | zero | nan
 define i1 @not_isnormalinf_or_uno_nofabs(half %x) #0 {
 ; CHECK-LABEL: @not_isnormalinf_or_uno_nofabs(
-; CHECK-NEXT:    [[OR:%.*]] = call i1 @llvm.is.fpclass.f16(half [[X:%.*]], i32 243)
+; CHECK-NEXT:    [[FABS:%.*]] = call half @llvm.fabs.f16(half [[X:%.*]])
+; CHECK-NEXT:    [[OR:%.*]] = fcmp ult half [[FABS]], 0xH0400
 ; CHECK-NEXT:    ret i1 [[OR]]
 ;
   %fabs = call half @llvm.fabs.f16(half %x)
diff --git a/llvm/test/Transforms/InstSimplify/logic-of-fcmps.ll b/llvm/test/Transforms/InstSimplify/logic-of-fcmps.ll
@@ -426,3 +426,68 @@ define i1 @olt_implies_olt_fail(float %x, float %y) {
   %ret = and i1 %olt, %olt2
   ret i1 %ret
 }
+
+define i1 @and_ord_olt_abs(float %x, float %y) {
+; CHECK-LABEL: @and_ord_olt_abs(
+; CHECK-NEXT:    [[ABSX:%.*]] = call float @llvm.fabs.f32(float [[X:%.*]])
+; CHECK-NEXT:    [[CMP2:%.*]] = fcmp olt float [[ABSX]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = fcmp ord float %x, 0.000000e+00
+  %absx = call float @llvm.fabs.f32(float %x)
+  %cmp2 = fcmp olt float %absx, %y
+  %and = and i1 %cmp1, %cmp2
+  ret i1 %and
+}
+
+define i1 @and_ord_olt_abs_commuted1(float %x, float %y) {
+; CHECK-LABEL: @and_ord_olt_abs_commuted1(
+; CHECK-NEXT:    [[ABSX:%.*]] = call float @llvm.fabs.f32(float [[X:%.*]])
+; CHECK-NEXT:    [[CMP2:%.*]] = fcmp olt float [[Y:%.*]], [[ABSX]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = fcmp ord float %x, 0.000000e+00
+  %absx = call float @llvm.fabs.f32(float %x)
+  %cmp2 = fcmp olt float %y, %absx
+  %and = and i1 %cmp1, %cmp2
+  ret i1 %and
+}
+
+define i1 @and_ord_olt_abs_commuted2(float %x, float %y) {
+; CHECK-LABEL: @and_ord_olt_abs_commuted2(
+; CHECK-NEXT:    [[ABSX:%.*]] = call float @llvm.fabs.f32(float [[X:%.*]])
+; CHECK-NEXT:    [[CMP2:%.*]] = fcmp olt float [[ABSX]], [[Y:%.*]]
+; CHECK-NEXT:    ret i1 [[CMP2]]
+;
+  %cmp1 = fcmp ord float %x, 0.000000e+00
+  %absx = call float @llvm.fabs.f32(float %x)
+  %cmp2 = fcmp olt float %absx, %y
+  %and = and i1 %cmp2, %cmp1
+  ret i1 %and
+}
+
+define i1 @or_ord_ult_abs(float %x, float %y) {
+; CHECK-LABEL: @or_ord_ult_abs(
+; CHECK-NEXT:    ret i1 true
+;
+  %cmp1 = fcmp ord float %x, 0.000000e+00
+  %absx = call float @llvm.fabs.f32(float %x)
+  %cmp2 = fcmp ult float %absx, %y
+  %or = or i1 %cmp1, %cmp2
+  ret i1 %or
+}
+
+define i1 @and_ord_olt_absz(float %x, float %y, float %z) {
+; CHECK-LABEL: @and_ord_olt_absz(
+; CHECK-NEXT:    [[CMP1:%.*]] = fcmp ord float [[X:%.*]], 0.000000e+00
+; CHECK-NEXT:    [[ABSZ:%.*]] = call float @llvm.fabs.f32(float [[Z:%.*]])
+; CHECK-NEXT:    [[CMP2:%.*]] = fcmp olt float [[ABSZ]], [[Y:%.*]]
+; CHECK-NEXT:    [[AND:%.*]] = and i1 [[CMP1]], [[CMP2]]
+; CHECK-NEXT:    ret i1 [[AND]]
+;
+  %cmp1 = fcmp ord float %x, 0.000000e+00
+  %absz = call float @llvm.fabs.f32(float %z)
+  %cmp2 = fcmp olt float %absz, %y
+  %and = and i1 %cmp1, %cmp2
+  ret i1 %and
+}
