instcombine: Migrate math library call simplifications

This patch migrates the math library call simplifications from the
simplify-libcalls pass into the instcombine library call simplifier.

I have typically migrated just one simplifier at a time, but the math
simplifiers are interdependent because:

   1. CosOpt, PowOpt, and Exp2Opt all depend on UnaryDoubleFPOpt.
   2. CosOpt, PowOpt, Exp2Opt, and UnaryDoubleFPOpt all depend on
      the option -enable-double-float-shrink.

These two factors made migrating each of these simplifiers individually
more of a pain than it would be worth.  So, I migrated them all together.

llvm-svn: 167815

1 files changed, 76 insertions, 0 deletions

diff --git a/llvm/test/Transforms/InstCombine/exp2-1.ll b/llvm/test/Transforms/InstCombine/exp2-1.ll
new file mode 100644
index 00000000000..1b0ad500041
--- /dev/null
+++ b/llvm/test/Transforms/InstCombine/exp2-1.ll
@@ -0,0 +1,76 @@
+; Test that the exp2 library call simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+declare double @exp2(double)
+declare float @exp2f(float)
+
+; Check exp2(sitofp(x)) -> ldexp(1.0, sext(x)).
+
+define double @test_simplify1(i32 %x) {
+; CHECK: @test_simplify1
+  %conv = sitofp i32 %x to double
+  %ret = call double @exp2(double %conv)
+; CHECK: call double @ldexp
+  ret double %ret
+}
+
+define double @test_simplify2(i16 signext %x) {
+; CHECK: @test_simplify2
+  %conv = sitofp i16 %x to double
+  %ret = call double @exp2(double %conv)
+; CHECK: call double @ldexp
+  ret double %ret
+}
+
+define double @test_simplify3(i8 signext %x) {
+; CHECK: @test_simplify3
+  %conv = sitofp i8 %x to double
+  %ret = call double @exp2(double %conv)
+; CHECK: call double @ldexp
+  ret double %ret
+}
+
+define float @test_simplify4(i32 %x) {
+; CHECK: @test_simplify4
+  %conv = sitofp i32 %x to float
+  %ret = call float @exp2f(float %conv)
+; CHECK: call float @ldexpf
+  ret float %ret
+}
+
+; Check exp2(uitofp(x)) -> ldexp(1.0, zext(x)).
+
+define double @test_no_simplify1(i32 %x) {
+; CHECK: @test_no_simplify1
+  %conv = uitofp i32 %x to double
+  %ret = call double @exp2(double %conv)
+; CHECK: call double @exp2
+  ret double %ret
+}
+
+define double @test_simplify6(i16 zeroext %x) {
+; CHECK: @test_simplify6
+  %conv = uitofp i16 %x to double
+  %ret = call double @exp2(double %conv)
+; CHECK: call double @ldexp
+  ret double %ret
+}
+
+define double @test_simplify7(i8 zeroext %x) {
+; CHECK: @test_simplify7
+  %conv = uitofp i8 %x to double
+  %ret = call double @exp2(double %conv)
+; CHECK: call double @ldexp
+  ret double %ret
+}
+
+define float @test_simplify8(i8 zeroext %x) {
+; CHECK: @test_simplify8
+  %conv = uitofp i8 %x to float
+  %ret = call float @exp2f(float %conv)
+; CHECK: call float @ldexpf
+  ret float %ret
+}