Changes in directory llvm/lib/Target/X86:
README.txt updated: 1.158 -> 1.159
---
Log message:
add generation of unnecessary push/pop around calls
---
Diffs of the changes: (+42 -0)
README.txt | 42 ++++++++++++++++++++++++++++++++++++++++++
1 files changed, 42 insertions(+)
Index: llvm/lib/Target/X86/README.txt
diff -u llvm/lib/Target/X86/README.txt:1.158
llvm/lib/Target/X86/README.txt:1.159
--- llvm/lib/Target/X86/README.txt:1.158 Wed Mar 14 16:03:53 2007
+++ llvm/lib/Target/X86/README.txt Wed Mar 21 16:16:39 2007
@@ -989,3 +989,45 @@
ret
//===---------------------------------------------------------------------===//
+
+We use push/pop of stack space around calls in situations where we don't have
to.
+Call to f below produces:
+ subl $16, %esp <<<<<
+ movl %eax, (%esp)
+ call L_f$stub
+ addl $16, %esp <<<<<
+The stack push/pop can be moved into the prolog/epilog. It does this because
it's
+building the frame pointer, but this should not be sufficient, only the use of
alloca
+should cause it to do this.
+(There are other issues shown by this code, but this is one.)
+
+typedef struct _range_t {
+ float fbias;
+ float fscale;
+ int ibias;
+ int iscale;
+ int ishift;
+ unsigned char lut[];
+} range_t;
+
+struct _decode_t {
+ int type:4;
+ int unit:4;
+ int alpha:8;
+ int N:8;
+ int bpc:8;
+ int bpp:16;
+ int skip:8;
+ int swap:8;
+ const range_t*const*range;
+};
+
+typedef struct _decode_t decode_t;
+
+extern int f(const decode_t* decode);
+
+int decode_byte (const decode_t* decode) {
+ if (decode->swap != 0)
+ return f(decode);
+ return 0;
+}
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