[llvm] r325262 - [InstCombine] test fdiv folds better; NFC

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Thu Feb 15 08:28:15 2018
New Revision: 325262

URL: http://llvm.org/viewvc/llvm-project?rev=325262&view=rev
Log:
[InstCombine] test fdiv folds better; NFC

We had redundant tests, but no tests for extra uses or vectors.
'fast' is an overly conservative requirement for these folds.

Modified:
    llvm/trunk/test/Transforms/InstCombine/fast-math.ll
    llvm/trunk/test/Transforms/InstCombine/fdiv.ll

Modified: llvm/trunk/test/Transforms/InstCombine/fast-math.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fast-math.ll?rev=325262&r1=325261&r2=325262&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fast-math.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/fast-math.ll Thu Feb 15 08:28:15 2018
@@ -477,30 +477,6 @@ define float @fdiv4(float %x) {
   ret float %div
 }
 
-; (X/Y)/Z = > X/(Y*Z)
-define float @fdiv5(float %f1, float %f2, float %f3) {
-; CHECK-LABEL: @fdiv5(
-; CHECK-NEXT:    [[TMP1:%.*]] = fmul float [[F2:%.*]], [[F3:%.*]]
-; CHECK-NEXT:    [[T2:%.*]] = fdiv fast float [[F1:%.*]], [[TMP1]]
-; CHECK-NEXT:    ret float [[T2]]
-;
-  %t1 = fdiv float %f1, %f2
-  %t2 = fdiv fast float %t1, %f3
-  ret float %t2
-}
-
-; Z/(X/Y) = > (Z*Y)/X
-define float @fdiv6(float %f1, float %f2, float %f3) {
-; CHECK-LABEL: @fdiv6(
-; CHECK-NEXT:    [[TMP1:%.*]] = fmul float [[F3:%.*]], [[F2:%.*]]
-; CHECK-NEXT:    [[T2:%.*]] = fdiv fast float [[TMP1]], [[F1:%.*]]
-; CHECK-NEXT:    ret float [[T2]]
-;
-  %t1 = fdiv float %f1, %f2
-  %t2 = fdiv fast float %f3, %t1
-  ret float %t2
-}
-
 ; C1/(X*C2) => (C1/C2) / X
 define float @fdiv7(float %x) {
 ; CHECK-LABEL: @fdiv7(

Modified: llvm/trunk/test/Transforms/InstCombine/fdiv.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/fdiv.ll?rev=325262&r1=325261&r2=325262&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/fdiv.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/fdiv.ll Thu Feb 15 08:28:15 2018
@@ -115,25 +115,59 @@ define <2 x float> @not_exact_inverse_ve
   ret <2 x float> %div
 }
 
-define float @test5(float %x, float %y, float %z) {
-; CHECK-LABEL: @test5(
-; CHECK-NEXT:    [[TMP1:%.*]] = fmul fast float [[Y:%.*]], [[Z:%.*]]
+; (X / Y) / Z --> X / (Y * Z)
+
+define float @div_with_div_numerator(float %x, float %y, float %z) {
+; CHECK-LABEL: @div_with_div_numerator(
+; CHECK-NEXT:    [[TMP1:%.*]] = fmul float [[Y:%.*]], [[Z:%.*]]
 ; CHECK-NEXT:    [[DIV2:%.*]] = fdiv fast float [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret float [[DIV2]]
 ;
-  %div1 = fdiv fast float %x, %y
+  %div1 = fdiv float %x, %y
+  %div2 = fdiv fast float %div1, %z
+  ret float %div2
+}
+
+; Z / (X / Y) --> (Z * Y) / X
+
+define <2 x float> @div_with_div_denominator(<2 x float> %x, <2 x float> %y, <2 x float> %z) {
+; CHECK-LABEL: @div_with_div_denominator(
+; CHECK-NEXT:    [[TMP1:%.*]] = fmul <2 x float> [[Z:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[DIV2:%.*]] = fdiv fast <2 x float> [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    ret <2 x float> [[DIV2]]
+;
+  %div1 = fdiv <2 x float> %x, %y
+  %div2 = fdiv fast <2 x float> %z, %div1
+  ret <2 x float> %div2
+}
+
+; Don't create an extra multiply if we can't eliminate the first div.
+
+declare void @use_f32(float)
+
+define float @div_with_div_numerator_extra_use(float %x, float %y, float %z) {
+; CHECK-LABEL: @div_with_div_numerator_extra_use(
+; CHECK-NEXT:    [[DIV1:%.*]] = fdiv float [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[DIV2:%.*]] = fdiv fast float [[DIV1]], [[Z:%.*]]
+; CHECK-NEXT:    call void @use_f32(float [[DIV1]])
+; CHECK-NEXT:    ret float [[DIV2]]
+;
+  %div1 = fdiv float %x, %y
   %div2 = fdiv fast float %div1, %z
+  call void @use_f32(float %div1)
   ret float %div2
 }
 
-define float @test6(float %x, float %y, float %z) {
-; CHECK-LABEL: @test6(
-; CHECK-NEXT:    [[TMP1:%.*]] = fmul fast float [[Z:%.*]], [[Y:%.*]]
-; CHECK-NEXT:    [[DIV2:%.*]] = fdiv fast float [[TMP1]], [[X:%.*]]
+define float @div_with_div_denominator_extra_use(float %x, float %y, float %z) {
+; CHECK-LABEL: @div_with_div_denominator_extra_use(
+; CHECK-NEXT:    [[DIV1:%.*]] = fdiv float [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT:    [[DIV2:%.*]] = fdiv fast float [[Z:%.*]], [[DIV1]]
+; CHECK-NEXT:    call void @use_f32(float [[DIV1]])
 ; CHECK-NEXT:    ret float [[DIV2]]
 ;
-  %div1 = fdiv fast float %x, %y
+  %div1 = fdiv float %x, %y
   %div2 = fdiv fast float %z, %div1
+  call void @use_f32(float %div1)
   ret float %div2
 }