[PATCH] D102574: [InstCombine] Missed optimization for pow(x, y) * pow(x, z) with fast-math

[Daniil Seredkin via Phabricator via llvm-commits]

vdsered updated this revision to Diff 350162.
vdsered added a comment.

Removed name diff in tests


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D102574/new/

https://reviews.llvm.org/D102574

Files:
  llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
  llvm/test/Transforms/InstCombine/fmul-pow.ll


Index: llvm/test/Transforms/InstCombine/fmul-pow.ll
===================================================================
--- llvm/test/Transforms/InstCombine/fmul-pow.ll
+++ llvm/test/Transforms/InstCombine/fmul-pow.ll
@@ -79,10 +79,9 @@
 
 define double @pow_ab_x_pow_ac_reassoc(double %a, double %b, double %c) {
 ; CHECK-LABEL: @pow_ab_x_pow_ac_reassoc(
-; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.pow.f64(double [[A:%.*]], double [[B:%.*]])
-; CHECK-NEXT:    [[TMP2:%.*]] = call double @llvm.pow.f64(double [[A]], double [[C:%.*]])
-; CHECK-NEXT:    [[MUL:%.*]] = fmul reassoc double [[TMP2]], [[TMP1]]
-; CHECK-NEXT:    ret double [[MUL]]
+; CHECK-NEXT:    [[TMP1:%.*]] = fadd reassoc double [[C:%.*]], [[B:%.*]]
+; CHECK-NEXT:    [[TMP2:%.*]] = call reassoc double @llvm.pow.f64(double [[A:%.*]], double [[TMP1]])
+; CHECK-NEXT:    ret double [[TMP2]]
 ;
   %1 = call double @llvm.pow.f64(double %a, double %b)
   %2 = call double @llvm.pow.f64(double %a, double %c)
@@ -90,12 +89,11 @@
   ret double %mul
 }
 
-
 define double @pow_ab_reassoc(double %a, double %b) {
 ; CHECK-LABEL: @pow_ab_reassoc(
-; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.pow.f64(double [[A:%.*]], double [[B:%.*]])
-; CHECK-NEXT:    [[MUL:%.*]] = fmul reassoc double [[TMP1]], [[TMP1]]
-; CHECK-NEXT:    ret double [[MUL]]
+; CHECK-NEXT:    [[TMP1:%.*]] = fadd reassoc double [[B:%.*]], [[B]]
+; CHECK-NEXT:    [[TMP2:%.*]] = call reassoc double @llvm.pow.f64(double [[A:%.*]], double [[TMP1]])
+; CHECK-NEXT:    ret double [[TMP2]]
 ;
   %1 = call double @llvm.pow.f64(double %a, double %b)
   %mul = fmul reassoc double %1, %1
@@ -118,10 +116,10 @@
 define double @pow_ab_x_pow_ac_reassoc_extra_use(double %a, double %b, double %c) {
 ; CHECK-LABEL: @pow_ab_x_pow_ac_reassoc_extra_use(
 ; CHECK-NEXT:    [[TMP1:%.*]] = call double @llvm.pow.f64(double [[A:%.*]], double [[B:%.*]])
-; CHECK-NEXT:    [[TMP2:%.*]] = call double @llvm.pow.f64(double [[A]], double [[C:%.*]])
-; CHECK-NEXT:    [[MUL:%.*]] = fmul reassoc double [[TMP1]], [[TMP2]]
+; CHECK-NEXT:    [[TMP2:%.*]] = fadd reassoc double [[B]], [[C:%.*]]
+; CHECK-NEXT:    [[TMP3:%.*]] = call reassoc double @llvm.pow.f64(double [[A]], double [[TMP2]])
 ; CHECK-NEXT:    call void @use(double [[TMP1]])
-; CHECK-NEXT:    ret double [[MUL]]
+; CHECK-NEXT:    ret double [[TMP3]]
 ;
   %1 = call double @llvm.pow.f64(double %a, double %b)
   %2 = call double @llvm.pow.f64(double %a, double %c)
Index: llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -555,22 +555,30 @@
       }
     }
 
-    // exp(X) * exp(Y) -> exp(X + Y)
-    if (match(Op0, m_Intrinsic<Intrinsic::exp>(m_Value(X))) &&
-        match(Op1, m_Intrinsic<Intrinsic::exp>(m_Value(Y))) &&
-        I.isOnlyUserOfAnyOperand()) {
-      Value *XY = Builder.CreateFAddFMF(X, Y, &I);
-      Value *Exp = Builder.CreateUnaryIntrinsic(Intrinsic::exp, XY, &I);
-      return replaceInstUsesWith(I, Exp);
-    }
+    if (I.isOnlyUserOfAnyOperand()) {
+      // pow(x, y) * pow(x, z) -> pow(x, y + z)
+      if (match(Op0, m_Intrinsic<Intrinsic::pow>(m_Value(X), m_Value(Y))) &&
+          match(Op1, m_Intrinsic<Intrinsic::pow>(m_Specific(X), m_Value(Z)))) {
+        auto *YZ = Builder.CreateFAddFMF(Y, Z, &I);
+        auto *NewPow = Builder.CreateBinaryIntrinsic(Intrinsic::pow, X, YZ, &I);
+        return replaceInstUsesWith(I, NewPow);
+      }
 
-    // exp2(X) * exp2(Y) -> exp2(X + Y)
-    if (match(Op0, m_Intrinsic<Intrinsic::exp2>(m_Value(X))) &&
-        match(Op1, m_Intrinsic<Intrinsic::exp2>(m_Value(Y))) &&
-        I.isOnlyUserOfAnyOperand()) {
-      Value *XY = Builder.CreateFAddFMF(X, Y, &I);
-      Value *Exp2 = Builder.CreateUnaryIntrinsic(Intrinsic::exp2, XY, &I);
-      return replaceInstUsesWith(I, Exp2);
+      // exp(X) * exp(Y) -> exp(X + Y)
+      if (match(Op0, m_Intrinsic<Intrinsic::exp>(m_Value(X))) &&
+          match(Op1, m_Intrinsic<Intrinsic::exp>(m_Value(Y)))) {
+        Value *XY = Builder.CreateFAddFMF(X, Y, &I);
+        Value *Exp = Builder.CreateUnaryIntrinsic(Intrinsic::exp, XY, &I);
+        return replaceInstUsesWith(I, Exp);
+      }
+
+      // exp2(X) * exp2(Y) -> exp2(X + Y)
+      if (match(Op0, m_Intrinsic<Intrinsic::exp2>(m_Value(X))) &&
+          match(Op1, m_Intrinsic<Intrinsic::exp2>(m_Value(Y)))) {
+        Value *XY = Builder.CreateFAddFMF(X, Y, &I);
+        Value *Exp2 = Builder.CreateUnaryIntrinsic(Intrinsic::exp2, XY, &I);
+        return replaceInstUsesWith(I, Exp2);
+      }
     }
 
     // (X*Y) * X => (X*X) * Y where Y != X


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