[PATCH] D64713: [InstCombine] X *fast (C ? 1.0 : 0.0) -> C ? X : 0.0

[Jay Foad via Phabricator via llvm-commits]

This revision was automatically updated to reflect the committed changes.
Closed by commit rG9323ef4ecca1: [InstCombine] Simplify binary op when only one operand is a select (authored by foad).

Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D64713/new/

https://reviews.llvm.org/D64713

Files:
  llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
  llvm/test/Transforms/InstCombine/fmul.ll
  llvm/test/Transforms/InstCombine/mul.ll


Index: llvm/test/Transforms/InstCombine/mul.ll
===================================================================
--- llvm/test/Transforms/InstCombine/mul.ll
+++ llvm/test/Transforms/InstCombine/mul.ll
@@ -599,9 +599,7 @@
 ; (C ? (X /exact Y) : 1) * Y -> C ? X : Y
 define i32 @mul_div_select(i32 %x, i32 %y, i1 %c) {
 ; CHECK-LABEL: @mul_div_select(
-; CHECK-NEXT:    [[DIV:%.*]] = udiv exact i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[C:%.*]], i32 [[DIV]], i32 1
-; CHECK-NEXT:    [[MUL:%.*]] = mul i32 [[SEL]], [[Y]]
+; CHECK-NEXT:    [[MUL:%.*]] = select i1 [[C:%.*]], i32 [[X:%.*]], i32 [[Y:%.*]]
 ; CHECK-NEXT:    ret i32 [[MUL]]
 ;
   %div = udiv exact i32 %x, %y
Index: llvm/test/Transforms/InstCombine/fmul.ll
===================================================================
--- llvm/test/Transforms/InstCombine/fmul.ll
+++ llvm/test/Transforms/InstCombine/fmul.ll
@@ -1073,8 +1073,7 @@
 ; X *fast (C ? 1.0 : 0.0) -> C ? X : 0.0
 define float @fmul_select(float %x, i1 %c) {
 ; CHECK-LABEL: @fmul_select(
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[C:%.*]], float 1.000000e+00, float 0.000000e+00
-; CHECK-NEXT:    [[MUL:%.*]] = fmul fast float [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    [[MUL:%.*]] = select fast i1 [[C:%.*]], float [[X:%.*]], float 0.000000e+00
 ; CHECK-NEXT:    ret float [[MUL]]
 ;
   %sel = select i1 %c, float 1.0, float 0.0
@@ -1085,8 +1084,7 @@
 ; X *fast (C ? 1.0 : 0.0) -> C ? X : 0.0
 define <2 x float> @fmul_select_vec(<2 x float> %x, i1 %c) {
 ; CHECK-LABEL: @fmul_select_vec(
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[C:%.*]], <2 x float> <float 1.000000e+00, float 1.000000e+00>, <2 x float> zeroinitializer
-; CHECK-NEXT:    [[MUL:%.*]] = fmul fast <2 x float> [[SEL]], [[X:%.*]]
+; CHECK-NEXT:    [[MUL:%.*]] = select fast i1 [[C:%.*]], <2 x float> [[X:%.*]], <2 x float> zeroinitializer
 ; CHECK-NEXT:    ret <2 x float> [[MUL]]
 ;
   %sel = select i1 %c, <2 x float> <float 1.0, float 1.0>, <2 x float> zeroinitializer
@@ -1110,8 +1108,7 @@
 define double @fmul_sqrt_select(double %x, i1 %c) {
 ; CHECK-LABEL: @fmul_sqrt_select(
 ; CHECK-NEXT:    [[SQR:%.*]] = call double @llvm.sqrt.f64(double [[X:%.*]])
-; CHECK-NEXT:    [[SEL:%.*]] = select i1 [[C:%.*]], double [[SQR]], double 1.000000e+00
-; CHECK-NEXT:    [[MUL:%.*]] = fmul fast double [[SQR]], [[SEL]]
+; CHECK-NEXT:    [[MUL:%.*]] = select fast i1 [[C:%.*]], double [[X]], double [[SQR]]
 ; CHECK-NEXT:    ret double [[MUL]]
 ;
   %sqr = call double @llvm.sqrt.f64(double %x)
Index: llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -788,6 +788,16 @@
       else if (True && !False)
         False = Builder.CreateBinOp(Opcode, C, F);
     }
+  } else if (LHSIsSelect && LHS->hasOneUse()) {
+    // (A ? B : C) op Y -> A ? (B op Y) : (C op Y)
+    Cond = A;
+    True = SimplifyBinOp(Opcode, B, RHS, FMF, Q);
+    False = SimplifyBinOp(Opcode, C, RHS, FMF, Q);
+  } else if (RHSIsSelect && RHS->hasOneUse()) {
+    // X op (D ? E : F) -> D ? (X op E) : (X op F)
+    Cond = D;
+    True = SimplifyBinOp(Opcode, LHS, E, FMF, Q);
+    False = SimplifyBinOp(Opcode, LHS, F, FMF, Q);
   }
 
   if (!True || !False)


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