bryant created this revision.
bryant added reviewers: spatel, RKSimon, majnemer.
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bryant set the repository for this revision to rL LLVM.
From IRC:
12:30:04 -!- Noxbru [~Noxbru at 170.red-2-139-2.dynamicip.rima-tde.net] has joined #llvm
12:32:20 < Noxbru> hi, I have a quick question about llvm: is there a way to make the optimizer optimize away the calls to 'round' when the arguments are known constants?
12:33:09 < Noxbru> for example, I have 'round(0.9)' and GCC -O2 simply puts a '1' while clang makes the full call to round
12:33:24 < Noxbru> at least when checking the assembly output
12:36:36 < Noxbru> BTW, this is with clang 3.9.0
12:38:10 < gronsaken> gamester: See the answer from Duncan in this thread https://groups.google.com/forum/#!topic/llvm-dev/uk4uiK93jeM
12:46:48 < davide> Noxbru: missing optimization in SimplifyLibCalls.cpp
12:46:58 < davide> Noxbru: open a bug
12:48:16 < Noxbru> davide: ah, okay, against which component should I file it?
12:48:33 < davide> scalar optimizations
12:48:39 < davide> libraries
12:48:49 < davide> it should be easy to fix, FWIW
Repository:
rL LLVM
https://reviews.llvm.org/D28110
Files:
lib/Analysis/ConstantFolding.cpp
test/Transforms/ConstProp/calls.ll
Index: test/Transforms/ConstProp/calls.ll
===================================================================
--- test/Transforms/ConstProp/calls.ll
+++ test/Transforms/ConstProp/calls.ll
@@ -16,6 +16,7 @@
declare double @log(double) readnone nounwind
declare double @log10(double) readnone nounwind
declare double @pow(double, double) readnone nounwind
+declare double @round(double) readnone nounwind
declare double @sin(double) readnone nounwind
declare double @sinh(double) readnone nounwind
declare double @sqrt(double) readnone nounwind
@@ -37,6 +38,7 @@
declare float @logf(float) readnone nounwind
declare float @log10f(float) readnone nounwind
declare float @powf(float, float) readnone nounwind
+declare float @roundf(float) readnone nounwind
declare float @sinf(float) readnone nounwind
declare float @sinhf(float) readnone nounwind
declare float @sqrtf(float) readnone nounwind
@@ -102,6 +104,9 @@
%14 = call double @pow(double 3.000000e+00, double 4.000000e+00)
store double %14, double* %slot
; FNOBUILTIN: call
+ %round_val = call double @round(double 3.000000e+00)
+ store double %round_val, double* %slot
+; FNOBUILTIN: call
%15 = call double @sinh(double 3.000000e+00)
store double %15, double* %slot
; FNOBUILTIN: call
@@ -153,6 +158,9 @@
%31 = call float @powf(float 3.000000e+00, float 4.000000e+00)
store float %31, float* %slotf
; FNOBUILTIN: call
+ %roundf_val = call float @roundf(float 3.000000e+00)
+ store float %roundf_val, float* %slotf
+; FNOBUILTIN: call
%32 = call float @sinf(float 3.000000e+00)
store float %32, float* %slotf
; FNOBUILTIN: call
Index: lib/Analysis/ConstantFolding.cpp
===================================================================
--- lib/Analysis/ConstantFolding.cpp
+++ lib/Analysis/ConstantFolding.cpp
@@ -1431,6 +1431,8 @@
Name == "log10f";
case 'p':
return Name == "pow" || Name == "powf";
+ case 'r':
+ return Name == "round" || Name == "roundf";
case 's':
return Name == "sin" || Name == "sinh" || Name == "sqrt" ||
Name == "sinf" || Name == "sinhf" || Name == "sqrtf";
@@ -1695,6 +1697,10 @@
}
}
break;
+ case 'r':
+ if ((Name == "round" && TLI->has(LibFunc::round)) ||
+ (Name == "roundf" && TLI->has(LibFunc::roundf)))
+ return ConstantFoldFP(round, V, Ty);
case 's':
if ((Name == "sin" && TLI->has(LibFunc::sin)) ||
(Name == "sinf" && TLI->has(LibFunc::sinf)))
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