[llvm-commits] CVS: llvm/lib/Target/X86/README.txt
Chris Lattner
lattner at cs.uiuc.edu
Tue Feb 7 22:52:18 PST 2006
Changes in directory llvm/lib/Target/X86:
README.txt updated: 1.47 -> 1.48
---
Log message:
Add some random notes, not high-prio
---
Diffs of the changes: (+21 -0)
README.txt | 21 +++++++++++++++++++++
1 files changed, 21 insertions(+)
Index: llvm/lib/Target/X86/README.txt
diff -u llvm/lib/Target/X86/README.txt:1.47 llvm/lib/Target/X86/README.txt:1.48
--- llvm/lib/Target/X86/README.txt:1.47 Tue Feb 7 02:35:44 2006
+++ llvm/lib/Target/X86/README.txt Wed Feb 8 00:52:06 2006
@@ -161,6 +161,14 @@
Combine: a = sin(x), b = cos(x) into a,b = sincos(x).
+Expand these to calls of sin/cos and stores:
+ double sincos(double x, double *sin, double *cos);
+ float sincosf(float x, float *sin, float *cos);
+ long double sincosl(long double x, long double *sin, long double *cos);
+
+Doing so could allow SROA of the destination pointers. See also:
+http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17687
+
//===---------------------------------------------------------------------===//
The instruction selector sometimes misses folding a load into a compare. The
@@ -386,3 +394,16 @@
The x86 backend currently supports dynamic-no-pic. Need to add asm
printer support for static and PIC.
+
+//===---------------------------------------------------------------------===//
+
+We should generate bts/btr/etc instructions on targets where they are cheap or
+when codesize is important. e.g., for:
+
+void setbit(int *target, int bit) {
+ *target |= (1 << bit);
+}
+void clearbit(int *target, int bit) {
+ *target &= ~(1 << bit);
+}
+
More information about the llvm-commits
mailing list