[InstCombine] add folds for minnum(-a, -b) --> -maxnum(a, b)

This is similar to what we do for integer min/max with 'not'
ops (rL321882).

This should fix:
https://bugs.llvm.org/show_bug.cgi?id=37404
https://bugs.llvm.org/show_bug.cgi?id=37405

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@332031 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineCalls.cpp b/lib/Transforms/InstCombine/InstCombineCalls.cpp
index c0c6a0d..d36380e 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -1952,8 +1952,24 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
       II->setArgOperand(1, Arg0);
       return II;
     }
+
+    // FIXME: Simplifications should be in instsimplify.
     if (Value *V = simplifyMinnumMaxnum(*II))
       return replaceInstUsesWith(*II, V);
+
+    Value *X, *Y;
+    if (match(Arg0, m_FNeg(m_Value(X))) && match(Arg1, m_FNeg(m_Value(Y))) &&
+        (Arg0->hasOneUse() || Arg1->hasOneUse())) {
+      // If both operands are negated, invert the call and negate the result:
+      // minnum(-X, -Y) --> -(maxnum(X, Y))
+      // maxnum(-X, -Y) --> -(minnum(X, Y))
+      Intrinsic::ID NewIID = II->getIntrinsicID() == Intrinsic::maxnum ?
+          Intrinsic::minnum : Intrinsic::maxnum;
+      Value *NewCall = Builder.CreateIntrinsic(NewIID, { X, Y }, II);
+      Instruction *FNeg = BinaryOperator::CreateFNeg(NewCall);
+      FNeg->copyIRFlags(II);
+      return FNeg;
+    }
     break;
   }
   case Intrinsic::fmuladd: {

diff --git a/test/Transforms/InstCombine/maxnum.ll b/test/Transforms/InstCombine/maxnum.ll
index 8a7c88b..11bff42 100644 (file)
--- a/test/Transforms/InstCombine/maxnum.ll
+++ b/test/Transforms/InstCombine/maxnum.ll
@@ -253,9 +253,8 @@ define float @fold_maxnum_f32_neginf_val(float %x) {
 
 define <2 x float> @neg_neg(<2 x float> %x, <2 x float> %y) {
 ; CHECK-LABEL: @neg_neg(
-; CHECK-NEXT:    [[NEGX:%.*]] = fsub <2 x float> <float -0.000000e+00, float -0.000000e+00>, [[X:%.*]]
-; CHECK-NEXT:    [[NEGY:%.*]] = fsub <2 x float> <float -0.000000e+00, float -0.000000e+00>, [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = call <2 x float> @llvm.maxnum.v2f32(<2 x float> [[NEGX]], <2 x float> [[NEGY]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call <2 x float> @llvm.minnum.v2f32(<2 x float> [[X:%.*]], <2 x float> [[Y:%.*]])
+; CHECK-NEXT:    [[R:%.*]] = fsub <2 x float> <float -0.000000e+00, float -0.000000e+00>, [[TMP1]]
 ; CHECK-NEXT:    ret <2 x float> [[R]]
 ;
   %negx = fsub <2 x float> <float -0.0, float -0.0>, %x
@@ -265,13 +264,11 @@ define <2 x float> @neg_neg(<2 x float> %x, <2 x float> %y) {
 }
 
 ; FMF is not required, but it should be propagated from the intrinsic (not the fnegs).
-; Also, make sure this works with vectors.
 
 define float @neg_neg_vec_fmf(float %x, float %y) {
 ; CHECK-LABEL: @neg_neg_vec_fmf(
-; CHECK-NEXT:    [[NEGX:%.*]] = fsub arcp float -0.000000e+00, [[X:%.*]]
-; CHECK-NEXT:    [[NEGY:%.*]] = fsub afn float -0.000000e+00, [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = call fast float @llvm.maxnum.f32(float [[NEGX]], float [[NEGY]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call fast float @llvm.minnum.f32(float [[X:%.*]], float [[Y:%.*]])
+; CHECK-NEXT:    [[R:%.*]] = fsub fast float -0.000000e+00, [[TMP1]]
 ; CHECK-NEXT:    ret float [[R]]
 ;
   %negx = fsub arcp float -0.0, %x
@@ -287,8 +284,8 @@ declare void @use(float)
 define float @neg_neg_extra_use_x(float %x, float %y) {
 ; CHECK-LABEL: @neg_neg_extra_use_x(
 ; CHECK-NEXT:    [[NEGX:%.*]] = fsub float -0.000000e+00, [[X:%.*]]
-; CHECK-NEXT:    [[NEGY:%.*]] = fsub float -0.000000e+00, [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = call float @llvm.maxnum.f32(float [[NEGX]], float [[NEGY]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.minnum.f32(float [[X]], float [[Y:%.*]])
+; CHECK-NEXT:    [[R:%.*]] = fsub float -0.000000e+00, [[TMP1]]
 ; CHECK-NEXT:    call void @use(float [[NEGX]])
 ; CHECK-NEXT:    ret float [[R]]
 ;
@@ -301,9 +298,9 @@ define float @neg_neg_extra_use_x(float %x, float %y) {
 
 define float @neg_neg_extra_use_y(float %x, float %y) {
 ; CHECK-LABEL: @neg_neg_extra_use_y(
-; CHECK-NEXT:    [[NEGX:%.*]] = fsub float -0.000000e+00, [[X:%.*]]
 ; CHECK-NEXT:    [[NEGY:%.*]] = fsub float -0.000000e+00, [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = call float @llvm.maxnum.f32(float [[NEGX]], float [[NEGY]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call float @llvm.minnum.f32(float [[X:%.*]], float [[Y]])
+; CHECK-NEXT:    [[R:%.*]] = fsub float -0.000000e+00, [[TMP1]]
 ; CHECK-NEXT:    call void @use(float [[NEGY]])
 ; CHECK-NEXT:    ret float [[R]]
 ;

diff --git a/test/Transforms/InstCombine/minnum.ll b/test/Transforms/InstCombine/minnum.ll
index dfc0406..a05ce8c 100644 (file)
--- a/test/Transforms/InstCombine/minnum.ll
+++ b/test/Transforms/InstCombine/minnum.ll
@@ -277,9 +277,8 @@ define float @fold_minnum_f32_minf_val(float %x) {
 
 define double @neg_neg(double %x, double %y) {
 ; CHECK-LABEL: @neg_neg(
-; CHECK-NEXT:    [[NEGX:%.*]] = fsub double -0.000000e+00, [[X:%.*]]
-; CHECK-NEXT:    [[NEGY:%.*]] = fsub double -0.000000e+00, [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = call double @llvm.minnum.f64(double [[NEGX]], double [[NEGY]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.maxnum.f64(double [[X:%.*]], double [[Y:%.*]])
+; CHECK-NEXT:    [[R:%.*]] = fsub double -0.000000e+00, [[TMP1]]
 ; CHECK-NEXT:    ret double [[R]]
 ;
   %negx = fsub double -0.0, %x
@@ -293,9 +292,8 @@ define double @neg_neg(double %x, double %y) {
 
 define <2 x double> @neg_neg_vec_fmf(<2 x double> %x, <2 x double> %y) {
 ; CHECK-LABEL: @neg_neg_vec_fmf(
-; CHECK-NEXT:    [[NEGX:%.*]] = fsub reassoc <2 x double> <double -0.000000e+00, double -0.000000e+00>, [[X:%.*]]
-; CHECK-NEXT:    [[NEGY:%.*]] = fsub fast <2 x double> <double -0.000000e+00, double -0.000000e+00>, [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = call nnan ninf <2 x double> @llvm.minnum.v2f64(<2 x double> [[NEGX]], <2 x double> [[NEGY]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call nnan ninf <2 x double> @llvm.maxnum.v2f64(<2 x double> [[X:%.*]], <2 x double> [[Y:%.*]])
+; CHECK-NEXT:    [[R:%.*]] = fsub nnan ninf <2 x double> <double -0.000000e+00, double -0.000000e+00>, [[TMP1]]
 ; CHECK-NEXT:    ret <2 x double> [[R]]
 ;
   %negx = fsub reassoc <2 x double> <double -0.0, double -0.0>, %x
@@ -311,8 +309,8 @@ declare void @use(double)
 define double @neg_neg_extra_use_x(double %x, double %y) {
 ; CHECK-LABEL: @neg_neg_extra_use_x(
 ; CHECK-NEXT:    [[NEGX:%.*]] = fsub double -0.000000e+00, [[X:%.*]]
-; CHECK-NEXT:    [[NEGY:%.*]] = fsub double -0.000000e+00, [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = call double @llvm.minnum.f64(double [[NEGX]], double [[NEGY]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.maxnum.f64(double [[X]], double [[Y:%.*]])
+; CHECK-NEXT:    [[R:%.*]] = fsub double -0.000000e+00, [[TMP1]]
 ; CHECK-NEXT:    call void @use(double [[NEGX]])
 ; CHECK-NEXT:    ret double [[R]]
 ;
@@ -325,9 +323,9 @@ define double @neg_neg_extra_use_x(double %x, double %y) {
 
 define double @neg_neg_extra_use_y(double %x, double %y) {
 ; CHECK-LABEL: @neg_neg_extra_use_y(
-; CHECK-NEXT:    [[NEGX:%.*]] = fsub double -0.000000e+00, [[X:%.*]]
 ; CHECK-NEXT:    [[NEGY:%.*]] = fsub double -0.000000e+00, [[Y:%.*]]
-; CHECK-NEXT:    [[R:%.*]] = call double @llvm.minnum.f64(double [[NEGX]], double [[NEGY]])
+; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.maxnum.f64(double [[X:%.*]], double [[Y]])
+; CHECK-NEXT:    [[R:%.*]] = fsub double -0.000000e+00, [[TMP1]]
 ; CHECK-NEXT:    call void @use(double [[NEGY]])
 ; CHECK-NEXT:    ret double [[R]]
 ;