llvm-6502/test/CodeGen
Sanjay Patel a4554c2897 Improve sqrt estimate algorithm (fast-math)
This patch changes the fast-math implementation for calculating sqrt(x) from:
y = 1 / (1 / sqrt(x))
to:
y = x * (1 / sqrt(x))

This has 2 benefits: less code / faster code and one less estimate instruction 
that may lose precision.

The only target that will be affected (until http://reviews.llvm.org/D5658 is approved)
is PPC. The difference in codegen for PPC is 2 less flops for a single-precision sqrtf
or vector sqrtf and 4 less flops for a double-precision sqrt. 
We also eliminate a constant load and extra register usage.

Differential Revision: http://reviews.llvm.org/D5682



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@219445 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-09 21:26:35 +00:00
..
AArch64 [AArch64] Generate vector signed/unsigned mul and mla/mls long. 2014-10-08 02:31:24 +00:00
ARM Emit unaligned access build attribute for ARM 2014-10-08 12:26:22 +00:00
CPP
Generic Revert "Revert "DI: Fold constant arguments into a single MDString"" 2014-10-03 20:01:09 +00:00
Hexagon Revert "Revert "DI: Fold constant arguments into a single MDString"" 2014-10-03 20:01:09 +00:00
Inputs Revert "Revert "DI: Fold constant arguments into a single MDString"" 2014-10-03 20:01:09 +00:00
Mips [mips] Return {f128} correctly for N32/N64. 2014-10-07 09:29:59 +00:00
MSP430 Drop the W postfix on the 16-bit registers. 2014-09-10 06:58:14 +00:00
NVPTX Revert r216862 due to a performance regression 2014-10-01 15:22:13 +00:00
PowerPC Improve sqrt estimate algorithm (fast-math) 2014-10-09 21:26:35 +00:00
R600 R600/SI: Legalize CopyToReg during instruction selection 2014-10-09 19:06:00 +00:00
SPARC Add back tests for empty function in SPARC and PowerPC. 2014-09-15 22:11:07 +00:00
SystemZ
Thumb Revert "Revert "DI: Fold constant arguments into a single MDString"" 2014-10-03 20:01:09 +00:00
Thumb2 [ARM] Allow selecting VRINT[APMXZR] and VCVT[BT] instructions for FPv5 2014-10-01 13:13:18 +00:00
X86 [AVX512] Intrinsics for vextract*x4 2014-10-08 23:25:37 +00:00
XCore Revert "Revert "DI: Fold constant arguments into a single MDString"" 2014-10-03 20:01:09 +00:00