[llvm] r345771 - [InstCombine] add tests for fmin/fmax pattern matching failure; NFC

[Sanjay Patel via llvm-commits]

Author: spatel
Date: Wed Oct 31 13:03:27 2018
New Revision: 345771

URL: http://llvm.org/viewvc/llvm-project?rev=345771&view=rev
Log:
[InstCombine] add tests for fmin/fmax pattern matching failure; NFC

Modified:
    llvm/trunk/test/Transforms/InstCombine/minmax-fp.ll

Modified: llvm/trunk/test/Transforms/InstCombine/minmax-fp.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/minmax-fp.ll?rev=345771&r1=345770&r2=345771&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/minmax-fp.ll (original)
+++ llvm/trunk/test/Transforms/InstCombine/minmax-fp.ll Wed Oct 31 13:03:27 2018
@@ -57,7 +57,10 @@ define double @t5(float %a) {
   ret double %3
 }
 
-; Signed zero, should not be converted
+; TODO:
+; From IEEE754: "Comparisons shall ignore the sign of zero (so +0 = −0)."
+; So the compare constant may be treated as +0.0, and we sink the fpext.
+
 define double @t6(float %a) {
 ; CHECK-LABEL: @t6(
 ; CHECK-NEXT:    [[TMP1:%.*]] = fcmp ult float [[A:%.*]], -0.000000e+00
@@ -71,7 +74,10 @@ define double @t6(float %a) {
   ret double %3
 }
 
-; Signed zero, should not be converted
+; TODO:
+; From IEEE754: "Comparisons shall ignore the sign of zero (so +0 = −0)."
+; So the compare constant may be treated as -0.0, and we sink the fpext.
+
 define double @t7(float %a) {
 ; CHECK-LABEL: @t7(
 ; CHECK-NEXT:    [[TMP1:%.*]] = fcmp ult float [[A:%.*]], 0.000000e+00
@@ -85,6 +91,42 @@ define double @t7(float %a) {
   ret double %3
 }
 
+; TODO:
+; min(min(x, 0.0), 0.0) --> min(x, 0.0)
+
+define float @fmin_fmin_zero_mismatch(float %x) {
+; CHECK-LABEL: @fmin_fmin_zero_mismatch(
+; CHECK-NEXT:    [[CMP1:%.*]] = fcmp olt float [[X:%.*]], -0.000000e+00
+; CHECK-NEXT:    [[MIN1:%.*]] = select i1 [[CMP1]], float [[X]], float 0.000000e+00
+; CHECK-NEXT:    [[CMP2:%.*]] = fcmp olt float [[MIN1]], 0.000000e+00
+; CHECK-NEXT:    [[MIN2:%.*]] = select i1 [[CMP2]], float [[MIN1]], float 0.000000e+00
+; CHECK-NEXT:    ret float [[MIN2]]
+;
+  %cmp1 = fcmp olt float %x, -0.0
+  %min1 = select i1 %cmp1, float %x, float 0.0
+  %cmp2 = fcmp olt float %min1, 0.0
+  %min2 = select i1 %cmp2, float %min1, float 0.0
+  ret float %min2
+}
+
+; TODO:
+; max(max(x, -0.0), -0.0) --> max(x, -0.0)
+
+define float @fmax_fmax_zero_mismatch(float %x) {
+; CHECK-LABEL: @fmax_fmax_zero_mismatch(
+; CHECK-NEXT:    [[CMP1:%.*]] = fcmp ogt float [[X:%.*]], 0.000000e+00
+; CHECK-NEXT:    [[MAX1:%.*]] = select i1 [[CMP1]], float [[X]], float -0.000000e+00
+; CHECK-NEXT:    [[CMP2:%.*]] = fcmp olt float [[MAX1]], 0.000000e+00
+; CHECK-NEXT:    [[MAX2:%.*]] = select i1 [[CMP2]], float -0.000000e+00, float [[MAX1]]
+; CHECK-NEXT:    ret float [[MAX2]]
+;
+  %cmp1 = fcmp ogt float %x, 0.0
+  %max1 = select i1 %cmp1, float %x, float -0.0
+  %cmp2 = fcmp ogt float 0.0, %max1
+  %max2 = select i1 %cmp2, float -0.0, float %max1
+  ret float %max2
+}
+
 define i64 @t8(float %a) {
 ; CHECK-LABEL: @t8(
 ; CHECK-NEXT:    [[DOTINV:%.*]] = fcmp oge float [[A:%.*]], 5.000000e+00